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	<meta charset="utf-8" /><meta name="hf:doc:metadata" content="{"title":"WordPiece tokenization","local":"wordpiece-tokenization","sections":[{"title":"Training algorithm","local":"training-algorithm","sections":[],"depth":2},{"title":"Tokenization algorithm","local":"tokenization-algorithm","sections":[],"depth":2},{"title":"Implementing WordPiece","local":"implementing-wordpiece","sections":[],"depth":2}],"depth":1}">
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	<link rel="modulepreload" href="/docs/course/pr_1069/th/_app/immutable/chunks/getInferenceSnippets.24b50994.js"><!-- HEAD_svelte-u9bgzb_START --><meta name="hf:doc:metadata" content="{"title":"WordPiece tokenization","local":"wordpiece-tokenization","sections":[{"title":"Training algorithm","local":"training-algorithm","sections":[],"depth":2},{"title":"Tokenization algorithm","local":"tokenization-algorithm","sections":[],"depth":2},{"title":"Implementing WordPiece","local":"implementing-wordpiece","sections":[],"depth":2}],"depth":1}"><!-- HEAD_svelte-u9bgzb_END --> <p></p> <h1 class="relative group"><a id="wordpiece-tokenization" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#wordpiece-tokenization"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>WordPiece tokenization</span></h1> <div class="flex space-x-1 absolute z-10 right-0 top-0"><a href="https://discuss.huggingface.co/t/chapter-6-questions" target="_blank"><img alt="Ask a Question" class="!m-0" src="https://img.shields.io/badge/Ask%20a%20question-ffcb4c.svg?logo=data:image/svg+xml;base64,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"></a> <a href="https://colab.research.google.com/github/huggingface/notebooks/blob/master/course/th/chapter6/section6.ipynb" target="_blank"><img alt="Open In Colab" class="!m-0" src="https://colab.research.google.com/assets/colab-badge.svg"></a> <a href="https://studiolab.sagemaker.aws/import/github/huggingface/notebooks/blob/master/course/th/chapter6/section6.ipynb" target="_blank"><img alt="Open In Studio Lab" class="!m-0" src="https://studiolab.sagemaker.aws/studiolab.svg"></a></div> <p data-svelte-h="svelte-s8wvje">WordPiece เป็นอัลกอริทึมสำหรับ tokenization ที่สร้างโดย Google เพื่อ pretrain โมเดล BERT หลังจากนั้นมันได้ถูกนำมาใช้กับโมเดลประเภท Transformer หลายตัวที่เป็นประเภทเดียวกับ BERT เช่น DistilBERT, MobileBERT, Funnel Transformers, และ MPNET</p> <p data-svelte-h="svelte-ssh6vl">WordPiece มีความคล้ายกับ BPE ในวิธีการเทรน แต่วิธีการแยกคำนั้นแตกต่างกัน</p> <iframe class="w-full xl:w-4/6 h-80" src="https://www.youtube-nocookie.com/embed/qpv6ms_t_1A" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> <div class="course-tip bg-gradient-to-br dark:bg-gradient-to-r before:border-green-500 dark:before:border-green-800 from-green-50 dark:from-gray-900 to-white dark:to-gray-950 border border-green-50 text-green-700 dark:text-gray-400"><p data-svelte-h="svelte-ndt3rq">💡 บทนี้จะพูดถึง WordPiece อย่างละเอียด เราจะเจาะลึกถึงไปถึงการ implement อัลกอริทึมนี้ คุณสามารถข้ามไปตอนท้ายได้ ถ้าคุณสนใจเพียงแค่ภาพรวมคร่าวๆเท่านั้น</p></div> <h2 class="relative group"><a id="training-algorithm" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#training-algorithm"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Training algorithm</span></h2> <div class="course-tip course-tip-orange bg-gradient-to-br dark:bg-gradient-to-r before:border-orange-500 dark:before:border-orange-800 from-orange-50 dark:from-gray-900 to-white dark:to-gray-950 border border-orange-50 text-orange-700 dark:text-gray-400"><p data-svelte-h="svelte-gt28yt">⚠️ เนื่องจาก Google ไม่เปิดเผยโค้ดสำหรับการเทรน WordPiece ดังนั้นโค้ดที่เราจะสอนคุณต่อจากนี้ มาจากการพยายามทำตามข้อมูลที่บอกไว้ใน paper แปลว่าโค้ดอาจจะไม่แม่นยำ 100%</p></div> <p data-svelte-h="svelte-1xzcaw9">เช่นเดียวกับ BPE อัลกอริทึม WordPiece เริ่มจาก vocabulary ขนาดเล็ก ที่ประกอบไปด้วย token พิเศษที่โมเดลใช้ และตัวอักษรตั้งต้น
	เพื่อที่โมเดลจะได้รู้ว่าคำไหนเป็นคำย่อย มันจะเขียน prefix เช่น <code>##</code> (ใช้ใน BERT) ไว้ข้างหน้าของแต่ละคำย่อย ในขั้นตอนแรก แต่ละคำจะถูกแบ่งออกเป็นตัวอักษร โดยตัวอักษรที่ไม่ใช่ตัวแรกจะมี prefix นี้</p> <p data-svelte-h="svelte-18px92m">ตัวอย่างเช่น คำว่า <code>"word"</code> จะถูกแบ่งดังนี้ :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->w ##o ##r ##d<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1b9hozx">ดังนั้น vocabulary ตั้งต้น จะประกอบไปด้วยทุกๆตัวอักษรที่อยู่เริ่มต้นของแต่ละคำ และตัวอักษรอื่นๆที่อยู่ข้างในคำนั้น ซึ่งนำหน้าด้วย prefix พิเศษ</p> <p>เช่นเดียวกันกับ BPE เป้าหมายในการเทรน WordPiece คือเรียนกฎเพื่อการ merge แต่ความแตกต่างคือหลักการในการเลือกคู่ token ที่จะนำมา merge แทนที่จะเลือกคู่ที่พบบ่อยที่สุด WordPiece จะคำนวณ score ให้แต่ละคู่ โดยใช้สูตรต่อไปนี้
	<!-- HTML_TAG_START --><span class="katex-display"><span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML" display="block"><semantics><mrow><mrow><mi mathvariant="normal">s</mi><mi mathvariant="normal">c</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">e</mi></mrow><mo>=</mo><mo stretchy="false">(</mo><mrow><mi mathvariant="normal">f</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">q</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">f</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">p</mi><mi mathvariant="normal">a</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">r</mi></mrow><mo stretchy="false">)</mo><mi mathvariant="normal">/</mi><mo stretchy="false">(</mo><mrow><mi mathvariant="normal">f</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">q</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">f</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">f</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">t</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">l</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">m</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">n</mi><mi mathvariant="normal">t</mi></mrow><mo>×</mo><mrow><mi mathvariant="normal">f</mi><mi mathvariant="normal">r</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">q</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">f</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">c</mi><mi mathvariant="normal">o</mi><mi mathvariant="normal">n</mi><mi mathvariant="normal">d</mi><mi mathvariant="normal">_</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">l</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">m</mi><mi mathvariant="normal">e</mi><mi mathvariant="normal">n</mi><mi mathvariant="normal">t</mi></mrow><mo stretchy="false">)</mo></mrow><annotation encoding="application/x-tex">\mathrm{score} = (\mathrm{freq\_of\_pair}) / (\mathrm{freq\_of\_first\_element} \times \mathrm{freq\_of\_second\_element})</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord"><span class="mord mathrm">score</span></span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1.06em;vertical-align:-0.31em;"></span><span class="mopen">(</span><span class="mord"><span class="mord mathrm">freq_of_pair</span></span><span class="mclose">)</span><span class="mord">/</span><span class="mopen">(</span><span class="mord"><span class="mord mathrm">freq_of_first_element</span></span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">×</span><span class="mspace" style="margin-right:0.2222em;"></span></span><span class="base"><span class="strut" style="height:1.06em;vertical-align:-0.31em;"></span><span class="mord"><span class="mord mathrm">freq_of_second_element</span></span><span class="mclose">)</span></span></span></span></span><!-- HTML_TAG_END --></p> <p data-svelte-h="svelte-g0e99l">การที่เราหารความถี่ของคู่ token ด้วยผลคูณของความถี่ของแต่ละ token ในคู่ จะทำให้อัลกอริทึมให้คะแนนคู่ ที่แต่ละ token มีความถี่ไม่สูง
	ตัวอย่างเช่น เราไม่จำเป็นจำต้อง merge <code>("un", "##able")</code> ถึงแม้ว่าคู่นี้จะมีจำนวนมากที่สุดใน vocabulary เพราะว่าทั้ง <code>"un"</code> และ <code>"##able"</code> ต่างพบได้กับคำอื่นๆด้วย และแต่ละตัวก็มีจำนวนค่อนข้างสูง
	ตรงกันข้ามกับ คู่เช่น <code>("hu", "##gging")</code> ซึ่งอาจจะถูกรวมเร็วกว่า (ในกรณีที่ “hugging” มีจำนวนสูงใน vocabulary ) เพราะว่า ทั้ง<code>"hu"</code> และ `“##gging” ต่างก็พบได้ไม่บ่อย</p> <p data-svelte-h="svelte-1ywco0h">เราจะใช้ตัวอย่าง เดียวกันกับที่เราใช้ใน BPE :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->(<span class="hljs-string">"hug"</span><span class="hljs-punctuation">,</span> <span class="hljs-number">10</span>)<span class="hljs-punctuation">,</span> (<span class="hljs-string">"pug"</span><span class="hljs-punctuation">,</span> <span class="hljs-number">5</span>)<span class="hljs-punctuation">,</span> (<span class="hljs-string">"pun"</span><span class="hljs-punctuation">,</span> <span class="hljs-number">12</span>)<span class="hljs-punctuation">,</span> (<span class="hljs-string">"bun"</span><span class="hljs-punctuation">,</span> <span class="hljs-number">4</span>)<span class="hljs-punctuation">,</span> (<span class="hljs-string">"hugs"</span><span class="hljs-punctuation">,</span> <span class="hljs-number">5</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-6hyjif">หลังจากการแยกแต่ละคำ เราจะได้ :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->(<span class="hljs-string">"h"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">10</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">5</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">12</span>), (<span class="hljs-string">"b"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">"h"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#s</span>"</span>, <span class="hljs-number">5</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-10hsbw2">ดังนั้น vocabulary ตั้งต้น คือ <code>["b", "h", "p", "##g", "##n", "##s", "##u"]</code> (เราขอละไม่พูดถึง token พิเศษในที่นี้)
	คู่ที่พบบ่อยที่สุดคือ <code>("##u", "##g")</code> ซึ่งพบ 20 ครั้ง แต่ว่าถ้านับจำนวนของแต่ละ token <code>"##u"</code> จะมีจำนวนค่อนข้างสูง ทำให้ score ของคู่นี้ไม่ได้สูงที่สุด (1 / 36)
	ทุกๆคู่ที่ประกอบด้วย <code>"##u"</code> จะได้ score เดียวกันซึ่งคือ (1 / 36) ดังนั้น score ที่สูงที่สุดจึงมาจากคู่ <code>("##g", "##s")</code> เพราะว่ามันไม่มี <code>"##u"</code> ซึ่งมี score เป็น 1 / 20 และกฎแรกที่เราได้ก็คือ <code>("##g", "##s") -> ("##gs")</code></p> <p data-svelte-h="svelte-1uqyw2y">โปรดสังเกตว่า เวลาที่เรา merge เราจะลบ ตัว <code>##</code> ออกระหว่าง token สองตัวที่เราต้องการจะ merge แปลว่าเราจะได้ <code>"##gs"</code> และเราจะเพิ่ม token นี้เข้าไปใน vocabulary จากนั้นเราก็จะใช้กฎนี้กับทุกๆคำใน corpus ด้วย :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->Vocabulary: [<span class="hljs-string">"b"</span>, <span class="hljs-string">"h"</span>, <span class="hljs-string">"p"</span>, <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#s</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#gs</span>"</span>]
	Corpus: (<span class="hljs-string">"h"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">10</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">5</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">12</span>), (<span class="hljs-string">"b"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">"h"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#gs</span>"</span>, <span class="hljs-number">5</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1xgh5rw">ตอนนี้ <code>"##u"</code> มีอยู่ในทุกๆคู่ แปลว่า ทุกคู่จะมี score เท่ากัน</p> <p data-svelte-h="svelte-1kgvvw9">ในกรณีนี้ เราจะเลือกกฎใดกฎหนึ่งเพื่อ merge ต่อไป เราจะเลือก <code>("h", "##u") -> "hu"</code> และได้ผลลัพธ์ต่อไปนี้ :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->Vocabulary: [<span class="hljs-string">"b"</span>, <span class="hljs-string">"h"</span>, <span class="hljs-string">"p"</span>, <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#s</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#gs</span>"</span>, <span class="hljs-string">"hu"</span>]
	Corpus: (<span class="hljs-string">"hu"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">10</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">5</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">12</span>), (<span class="hljs-string">"b"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">"hu"</span> <span class="hljs-string">"#<span class="hljs-subst">#gs</span>"</span>, <span class="hljs-number">5</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1bf7daq">ตอนนี้คู่ที่มี score สูงที่สุดคือ <code>("hu", "##g")</code> และ <code>("hu", "##gs")</code> ซึ่งทั้งสองมี score เท่ากับ 1/15 (ส่วนตัวอื่นๆที่เหลือ มี score เท่ากับ 1/21) เราจะเลือกคู่แรกใน list มาใช้ เพื่อ merge :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->Vocabulary: [<span class="hljs-string">"b"</span>, <span class="hljs-string">"h"</span>, <span class="hljs-string">"p"</span>, <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#s</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span>, <span class="hljs-string">"#<span class="hljs-subst">#gs</span>"</span>, <span class="hljs-string">"hu"</span>, <span class="hljs-string">"hug"</span>]
	Corpus: (<span class="hljs-string">"hug"</span>, <span class="hljs-number">10</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#g</span>"</span>, <span class="hljs-number">5</span>), (<span class="hljs-string">"p"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">12</span>), (<span class="hljs-string">"b"</span> <span class="hljs-string">"#<span class="hljs-subst">#u</span>"</span> <span class="hljs-string">"#<span class="hljs-subst">#n</span>"</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">"hu"</span> <span class="hljs-string">"#<span class="hljs-subst">#gs</span>"</span>, <span class="hljs-number">5</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-rselkw">เราจะทำแบบนี้จนกว่าจะได้ vocabulary ที่มีขนาดใหญ่มากพอ</p> <div class="course-tip bg-gradient-to-br dark:bg-gradient-to-r before:border-green-500 dark:before:border-green-800 from-green-50 dark:from-gray-900 to-white dark:to-gray-950 border border-green-50 text-green-700 dark:text-gray-400"><p data-svelte-h="svelte-qdffzs">✏️ <strong>ตาคุณบ้างแล้ว!</strong> กฎ merge ต่อไปคืออะไร</p></div> <h2 class="relative group"><a id="tokenization-algorithm" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#tokenization-algorithm"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Tokenization algorithm</span></h2> <p data-svelte-h="svelte-1ergz1y">การ tokenization ใน WordPiece แตกต่างจาก BPE ตรงที่ WordPiece จะบันทึกเฉพาะ vocabulary สุดท้ายเท่านั้น และไม่ได้บันทึก กฎ merge
	หากเราจะ tokenize คำใดคำหนึ่ง WordPiece จะหาคำย่อยที่ยาวที่สุด ที่พบใน vocabulary จากนั้นจะแยกคำออกตามนั้น
	ตัวอย่างเช่น ถ้าเราใช้ vocabulary ที่เทรนแล้วจากตัวอย่างด้านบน และต้องการ tokenize คำว่า <code>"hugs"</code> คำย่อยที่ยาวที่สุดก็คือ <code>"hug"</code> ดังนั้น เราจะแบ่งมันออกเป็น <code>["hug", "##s"]</code>
	จากนั้นเราก็จะดูที่ <code>"##s"</code> เราพบว่าเป็น token ที่อยู่ใน vocabulary ดังนั้น เราจึงได้ <code>["hug", "##s"]</code>
	ถ้าเราใช้ BPE เราจะใช้กฎที่เทรนมาตามลำดับ ซึ่งมันจะ tokenize ตัวอย่างของเราออกเป็น <code>["hu", "##gs"]</code></p> <p data-svelte-h="svelte-oxstdp">มาดูอีกตัวอย่างกัน เช่นคำว่า <code>"bugs"</code>
	เราจะเริ่มอ่านจากข้างหน้าของคำไปข้างหลัง คุณจะเห็นว่า <code>"b"</code> เป็นคำย่อยที่ยาวที่สุดที่พบใน vocabulary ดังนั้น เราจะแยกคำตรงนี้ และเราจะได้ <code>["b", "##ugs"]</code>
	จากนั้นเราจะดูคำว่า <code>"##ugs"</code> สำหรับคำนี้เราพบว่า <code>"##u"</code> คือคำย่อยที่ยาวที่สุดที่พบใน vocabulary ดังนั้น เราจึงจะแยกคำตรงนี้ และได้ผลลัพธ์เป็น <code>["b", "##u, "##gs"]</code>
	สุดท้ายเราจะดูที่คำว่า <code>"##gs"</code> ซึ่งเราพบว่า มันอยู่ใน vocabulary แล้ว ดังนั้นเราไม่ต้องแบ่งมันอีก</p> <p data-svelte-h="svelte-akd6a0">ในกรณีที่เราไม่สามารถหาคำย่อยที่อยู่ใน vocabulary ได้เลย คำหลักที่เรากำลังอ่านนั้นจะถูกแปลงเป็นคำ unknown
	ตัวอย่างเช่นคำว่า <code>"mug"</code> จะถูก tokenize ให้เป็น <code>["[UNK]"]</code> เช่นเดียวกันกับคำว่า <code>"bum"</code> ถึงแม้ว่าเราจะเจอ <code>"b"</code> และ <code>"##u"</code> ใน vocabulary แต่ว่า <code>"##m"</code> ไม่ได้อยู่ใน vocabulary เราจะแปลงทั้งคำเป็น <code>["[UNK]"]</code> และจะไม่แยกมันเป็น <code>["b", "##u", "[UNK]"]</code>
	นี่เป็นสิ่งหนึ่งที่แตกต่างจาก BPE โดย BPE จะดูที่แต่ละตัวอักษร และถ้าตัวไหนไม่พบใน vocabulary ก็จะถูกคัดว่าเป็น unknown</p> <div class="course-tip bg-gradient-to-br dark:bg-gradient-to-r before:border-green-500 dark:before:border-green-800 from-green-50 dark:from-gray-900 to-white dark:to-gray-950 border border-green-50 text-green-700 dark:text-gray-400"><p data-svelte-h="svelte-5m52ga">✏️ <strong>ถึงตาคุณแล้ว!</strong> คำว่า <code>"pugs"</code> จะถูก tokenize อย่างไร?</p></div> <h2 class="relative group"><a id="implementing-wordpiece" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#implementing-wordpiece"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Implementing WordPiece</span></h2> <p data-svelte-h="svelte-rd9398">มาดูกันว่า เราจะ implement อัลกอริทึม WordPiece ได้อย่างไร
	เช่นเดียวกับตอนที่เราสอนเรื่อง BPE สิ่งที่เราจะสอนต่อไปนี้เป็นเพียงตัวอย่าง เพื่อให้คุณเข้าใจการทำงานของอัลกอริทึม โค้ดที่ได้อาจจะไม่สามารถใช้ได้กับ corpus ใหญ่ๆ
	เราจะใช้ corpus ตัวอย่างเดียวกับที่ใช้ในบท BPE :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->corpus = [
	<span class="hljs-string">"This is the Hugging Face course."</span>,
	<span class="hljs-string">"This chapter is about tokenization."</span>,
	<span class="hljs-string">"This section shows several tokenizer algorithms."</span>,
	<span class="hljs-string">"Hopefully, you will be able to understand how they are trained and generate tokens."</span>,
	]<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1e3v7ug">ก่อนอื่นคุณจะต้อง pre-tokenize corpus เพื่อแยกข้อความเป็นคำๆ เนื่องจากเราจะจำลองการทำงานของ WordPiece tokenizer (เช่น BERT) เราจะใช้ <code>bert-base-cased</code> tokenizer ในการ pre-tokenize</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-keyword">from</span> transformers <span class="hljs-keyword">import</span> AutoTokenizer

	tokenizer = AutoTokenizer.from_pretrained(<span class="hljs-string">"bert-base-cased"</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-96qu0m">จากนั้นคำนวณความถี่ของแต่ละคำใน corpus :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-keyword">from</span> collections <span class="hljs-keyword">import</span> defaultdict

	word_freqs = defaultdict(<span class="hljs-built_in">int</span>)
	<span class="hljs-keyword">for</span> text <span class="hljs-keyword">in</span> corpus:
	words_with_offsets = tokenizer.backend_tokenizer.pre_tokenizer.pre_tokenize_str(text)
	new_words = [word <span class="hljs-keyword">for</span> word, offset <span class="hljs-keyword">in</span> words_with_offsets]
	<span class="hljs-keyword">for</span> word <span class="hljs-keyword">in</span> new_words:
	word_freqs[word] += <span class="hljs-number">1</span>

	word_freqs<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->defaultdict(
	<span class="hljs-built_in">int</span>, {<span class="hljs-string">'This'</span>: <span class="hljs-number">3</span>, <span class="hljs-string">'is'</span>: <span class="hljs-number">2</span>, <span class="hljs-string">'the'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'Hugging'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'Face'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'Course'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'.'</span>: <span class="hljs-number">4</span>, <span class="hljs-string">'chapter'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'about'</span>: <span class="hljs-number">1</span>,
	<span class="hljs-string">'tokenization'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'section'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'shows'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'several'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'tokenizer'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'algorithms'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'Hopefully'</span>: <span class="hljs-number">1</span>,
	<span class="hljs-string">','</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'you'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'will'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'be'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'able'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'to'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'understand'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'how'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'they'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'are'</span>: <span class="hljs-number">1</span>,
	<span class="hljs-string">'trained'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'and'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'generate'</span>: <span class="hljs-number">1</span>, <span class="hljs-string">'tokens'</span>: <span class="hljs-number">1</span>})<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-7js4ic">เราจะมาสร้างเซ็ตของ alphabet กัน ซึ่งคือเซ็ตที่ประกอบไปด้วยตัวอักษรแรกของแต่ละคำ และอักษรอื่นๆที่ไม่ใช่ตัวแรกจะมีการใส่ <code>##</code> ไว้ข้างหน้า :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->alphabet = []
	<span class="hljs-keyword">for</span> word <span class="hljs-keyword">in</span> word_freqs.keys():
	<span class="hljs-keyword">if</span> word[<span class="hljs-number">0</span>] <span class="hljs-keyword">not</span> <span class="hljs-keyword">in</span> alphabet:
	alphabet.append(word[<span class="hljs-number">0</span>])
	<span class="hljs-keyword">for</span> letter <span class="hljs-keyword">in</span> word[<span class="hljs-number">1</span>:]:
	<span class="hljs-keyword">if</span> <span class="hljs-string">f"##<span class="hljs-subst">{letter}</span>"</span> <span class="hljs-keyword">not</span> <span class="hljs-keyword">in</span> alphabet:
	alphabet.append(<span class="hljs-string">f"##<span class="hljs-subst">{letter}</span>"</span>)

	alphabet.sort()
	alphabet

	<span class="hljs-built_in">print</span>(alphabet)<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->[<span class="hljs-string">'##a'</span>, <span class="hljs-string">'##b'</span>, <span class="hljs-string">'##c'</span>, <span class="hljs-string">'##d'</span>, <span class="hljs-string">'##e'</span>, <span class="hljs-string">'##f'</span>, <span class="hljs-string">'##g'</span>, <span class="hljs-string">'##h'</span>, <span class="hljs-string">'##i'</span>, <span class="hljs-string">'##k'</span>, <span class="hljs-string">'##l'</span>, <span class="hljs-string">'##m'</span>, <span class="hljs-string">'##n'</span>, <span class="hljs-string">'##o'</span>, <span class="hljs-string">'##p'</span>, <span class="hljs-string">'##r'</span>, <span class="hljs-string">'##s'</span>,
	<span class="hljs-string">'##t'</span>, <span class="hljs-string">'##u'</span>, <span class="hljs-string">'##v'</span>, <span class="hljs-string">'##w'</span>, <span class="hljs-string">'##y'</span>, <span class="hljs-string">'##z'</span>, <span class="hljs-string">','</span>, <span class="hljs-string">'.'</span>, <span class="hljs-string">'C'</span>, <span class="hljs-string">'F'</span>, <span class="hljs-string">'H'</span>, <span class="hljs-string">'T'</span>, <span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>, <span class="hljs-string">'g'</span>, <span class="hljs-string">'h'</span>, <span class="hljs-string">'i'</span>, <span class="hljs-string">'s'</span>, <span class="hljs-string">'t'</span>, <span class="hljs-string">'u'</span>,
	<span class="hljs-string">'w'</span>, <span class="hljs-string">'y'</span>]<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1203ni3">เราจะเพิ่ม token พิเศษ เข้าไปด้านหน้าของ list นี้ด้วย สำหรับ BERT คือ <code>["[PAD]", "[UNK]", "[CLS]", "[SEP]", "[MASK]"]</code> :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->vocab = [<span class="hljs-string">"[PAD]"</span>, <span class="hljs-string">"[UNK]"</span>, <span class="hljs-string">"[CLS]"</span>, <span class="hljs-string">"[SEP]"</span>, <span class="hljs-string">"[MASK]"</span>] + alphabet.copy()<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-18t34je">จากนั้น เราจะทำการแยกแต่ละคำกัน โดยแยกตัวอักษรแรกออกมา และตัวที่เหลือจะเพิ่ม <code>##</code> ไว้ข้างหน้า :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->splits = {
	word: [c <span class="hljs-keyword">if</span> i == <span class="hljs-number">0</span> <span class="hljs-keyword">else</span> <span class="hljs-string">f"##<span class="hljs-subst">{c}</span>"</span> <span class="hljs-keyword">for</span> i, c <span class="hljs-keyword">in</span> <span class="hljs-built_in">enumerate</span>(word)]
	<span class="hljs-keyword">for</span> word <span class="hljs-keyword">in</span> word_freqs.keys()
	}<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-162ij5l">ตอนนี้เราก็พร้อมที่จะเทรนแล้ว เราจะมาเขียนฟังก์ชันเพื่อคำนวณ score ให้แต่ละคู่ tokenกัน :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-keyword">def</span> <span class="hljs-title function_">compute_pair_scores</span>(<span class="hljs-params">splits</span>):
	letter_freqs = defaultdict(<span class="hljs-built_in">int</span>)
	pair_freqs = defaultdict(<span class="hljs-built_in">int</span>)
	<span class="hljs-keyword">for</span> word, freq <span class="hljs-keyword">in</span> word_freqs.items():
	split = splits[word]
	<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(split) == <span class="hljs-number">1</span>:
	letter_freqs[split[<span class="hljs-number">0</span>]] += freq
	<span class="hljs-keyword">continue</span>
	<span class="hljs-keyword">for</span> i <span class="hljs-keyword">in</span> <span class="hljs-built_in">range</span>(<span class="hljs-built_in">len</span>(split) - <span class="hljs-number">1</span>):
	pair = (split[i], split[i + <span class="hljs-number">1</span>])
	letter_freqs[split[i]] += freq
	pair_freqs[pair] += freq
	letter_freqs[split[-<span class="hljs-number">1</span>]] += freq

	scores = {
	pair: freq / (letter_freqs[pair[<span class="hljs-number">0</span>]] * letter_freqs[pair[<span class="hljs-number">1</span>]])
	<span class="hljs-keyword">for</span> pair, freq <span class="hljs-keyword">in</span> pair_freqs.items()
	}
	<span class="hljs-keyword">return</span> scores<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-14bnpwr">มาดูกันว่าผลลัพธ์ที่ได้หลังจากการรันครั้งแรกเป็นอย่างไร :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->pair_scores = compute_pair_scores(splits)
	<span class="hljs-keyword">for</span> i, key <span class="hljs-keyword">in</span> <span class="hljs-built_in">enumerate</span>(pair_scores.keys()):
	<span class="hljs-built_in">print</span>(<span class="hljs-string">f"<span class="hljs-subst">{key}</span>: <span class="hljs-subst">{pair_scores[key]}</span>"</span>)
	<span class="hljs-keyword">if</span> i >= <span class="hljs-number">5</span>:
	<span class="hljs-keyword">break</span><!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->(<span class="hljs-string">'T'</span>, <span class="hljs-string">'##h'</span>): <span class="hljs-number">0.125</span>
	(<span class="hljs-string">'##h'</span>, <span class="hljs-string">'##i'</span>): <span class="hljs-number">0.03409090909090909</span>
	(<span class="hljs-string">'##i'</span>, <span class="hljs-string">'##s'</span>): <span class="hljs-number">0.02727272727272727</span>
	(<span class="hljs-string">'i'</span>, <span class="hljs-string">'##s'</span>): <span class="hljs-number">0.1</span>
	(<span class="hljs-string">'t'</span>, <span class="hljs-string">'##h'</span>): <span class="hljs-number">0.03571428571428571</span>
	(<span class="hljs-string">'##h'</span>, <span class="hljs-string">'##e'</span>): <span class="hljs-number">0.011904761904761904</span><!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-7ry0n2">จากนั้น เราจะหาคู่ที่มี score สูงที่สุด โดยใช้ loop ง่ายๆ ดังนี้ :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->best_pair = <span class="hljs-string">""</span>
	max_score = <span class="hljs-literal">None</span>
	<span class="hljs-keyword">for</span> pair, score <span class="hljs-keyword">in</span> pair_scores.items():
	<span class="hljs-keyword">if</span> max_score <span class="hljs-keyword">is</span> <span class="hljs-literal">None</span> <span class="hljs-keyword">or</span> max_score < score:
	best_pair = pair
	max_score = score

	<span class="hljs-built_in">print</span>(best_pair, max_score)<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->(<span class="hljs-string">'a'</span>, <span class="hljs-string">'##b'</span>) <span class="hljs-number">0.2</span><!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1mxdgvs">กฎที่ได้จากการเทรนครั้งแรกคือ <code>('a', '##b') -> 'ab'</code> ดังนั้นเราจะเพิ่ม <code>'ab'</code> เข้าไปใน vocabulary :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->vocab.append(<span class="hljs-string">"ab"</span>)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1a55hu1">ก่อนที่จะทำต่อ เราจะต้องเพิ่มตัวที่ถูก merge เข้าไปใน dictionary <code>splits</code> ก่อน โดยเราจะเขียนฟังก์ชันเพื่อการคำนวณนี้ :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-keyword">def</span> <span class="hljs-title function_">merge_pair</span>(<span class="hljs-params">a, b, splits</span>):
	<span class="hljs-keyword">for</span> word <span class="hljs-keyword">in</span> word_freqs:
	split = splits[word]
	<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(split) == <span class="hljs-number">1</span>:
	<span class="hljs-keyword">continue</span>
	i = <span class="hljs-number">0</span>
	<span class="hljs-keyword">while</span> i < <span class="hljs-built_in">len</span>(split) - <span class="hljs-number">1</span>:
	<span class="hljs-keyword">if</span> split[i] == a <span class="hljs-keyword">and</span> split[i + <span class="hljs-number">1</span>] == b:
	merge = a + b[<span class="hljs-number">2</span>:] <span class="hljs-keyword">if</span> b.startswith(<span class="hljs-string">"##"</span>) <span class="hljs-keyword">else</span> a + b
	split = split[:i] + [merge] + split[i + <span class="hljs-number">2</span> :]
	<span class="hljs-keyword">else</span>:
	i += <span class="hljs-number">1</span>
	splits[word] = split
	<span class="hljs-keyword">return</span> splits<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-13vg1su">นี่คือผลลัพธ์ของการ merge ครั้งแรก :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->splits = merge_pair(<span class="hljs-string">"a"</span>, <span class="hljs-string">"##b"</span>, splits)
	splits[<span class="hljs-string">"about"</span>]<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->[<span class="hljs-string">'ab'</span>, <span class="hljs-string">'##o'</span>, <span class="hljs-string">'##u'</span>, <span class="hljs-string">'##t'</span>]<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1swaphm">ตอนนี้เราก็มีทุกฟังก์ชันที่จำเป็นสำหรับการเทรนแล้ว เราจะเทรนจนกว่า tokenizer ได้เรียนเกี่ยวกับทุกๆ merge ที่เราต้องการ เราจะตั้งค่าขนาด vocabulary เป็น 70 สำหรับตัวอย่างนี้ :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->vocab_size = <span class="hljs-number">70</span>
	<span class="hljs-keyword">while</span> <span class="hljs-built_in">len</span>(vocab) < vocab_size:
	scores = compute_pair_scores(splits)
	best_pair, max_score = <span class="hljs-string">""</span>, <span class="hljs-literal">None</span>
	<span class="hljs-keyword">for</span> pair, score <span class="hljs-keyword">in</span> scores.items():
	<span class="hljs-keyword">if</span> max_score <span class="hljs-keyword">is</span> <span class="hljs-literal">None</span> <span class="hljs-keyword">or</span> max_score < score:
	best_pair = pair
	max_score = score
	splits = merge_pair(*best_pair, splits)
	new_token = (
	best_pair[<span class="hljs-number">0</span>] + best_pair[<span class="hljs-number">1</span>][<span class="hljs-number">2</span>:]
	<span class="hljs-keyword">if</span> best_pair[<span class="hljs-number">1</span>].startswith(<span class="hljs-string">"##"</span>)
	<span class="hljs-keyword">else</span> best_pair[<span class="hljs-number">0</span>] + best_pair[<span class="hljs-number">1</span>]
	)
	vocab.append(new_token)<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-bss46k">มาดูผลลัพธ์ของ vocabulary กัน :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-built_in">print</span>(vocab)<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->[<span class="hljs-string">'[PAD]'</span>, <span class="hljs-string">'[UNK]'</span>, <span class="hljs-string">'[CLS]'</span>, <span class="hljs-string">'[SEP]'</span>, <span class="hljs-string">'[MASK]'</span>, <span class="hljs-string">'##a'</span>, <span class="hljs-string">'##b'</span>, <span class="hljs-string">'##c'</span>, <span class="hljs-string">'##d'</span>, <span class="hljs-string">'##e'</span>, <span class="hljs-string">'##f'</span>, <span class="hljs-string">'##g'</span>, <span class="hljs-string">'##h'</span>, <span class="hljs-string">'##i'</span>, <span class="hljs-string">'##k'</span>,
	<span class="hljs-string">'##l'</span>, <span class="hljs-string">'##m'</span>, <span class="hljs-string">'##n'</span>, <span class="hljs-string">'##o'</span>, <span class="hljs-string">'##p'</span>, <span class="hljs-string">'##r'</span>, <span class="hljs-string">'##s'</span>, <span class="hljs-string">'##t'</span>, <span class="hljs-string">'##u'</span>, <span class="hljs-string">'##v'</span>, <span class="hljs-string">'##w'</span>, <span class="hljs-string">'##y'</span>, <span class="hljs-string">'##z'</span>, <span class="hljs-string">','</span>, <span class="hljs-string">'.'</span>, <span class="hljs-string">'C'</span>, <span class="hljs-string">'F'</span>, <span class="hljs-string">'H'</span>,
	<span class="hljs-string">'T'</span>, <span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>, <span class="hljs-string">'g'</span>, <span class="hljs-string">'h'</span>, <span class="hljs-string">'i'</span>, <span class="hljs-string">'s'</span>, <span class="hljs-string">'t'</span>, <span class="hljs-string">'u'</span>, <span class="hljs-string">'w'</span>, <span class="hljs-string">'y'</span>, <span class="hljs-string">'##fu'</span>, <span class="hljs-string">'Fa'</span>, <span class="hljs-string">'Fac'</span>, <span class="hljs-string">'##ct'</span>, <span class="hljs-string">'##ful'</span>, <span class="hljs-string">'##full'</span>, <span class="hljs-string">'##fully'</span>,
	<span class="hljs-string">'Th'</span>, <span class="hljs-string">'ch'</span>, <span class="hljs-string">'##hm'</span>, <span class="hljs-string">'cha'</span>, <span class="hljs-string">'chap'</span>, <span class="hljs-string">'chapt'</span>, <span class="hljs-string">'##thm'</span>, <span class="hljs-string">'Hu'</span>, <span class="hljs-string">'Hug'</span>, <span class="hljs-string">'Hugg'</span>, <span class="hljs-string">'sh'</span>, <span class="hljs-string">'th'</span>, <span class="hljs-string">'is'</span>, <span class="hljs-string">'##thms'</span>, <span class="hljs-string">'##za'</span>, <span class="hljs-string">'##zat'</span>,
	<span class="hljs-string">'##ut'</span>]<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-jcpg6w">ถ้าเทียบกับ BPE คุณจะเห็นว่า tokenizer ตัวนี้สามารถเรียนเกี่ยวกับคำย่อยได้เร็วกว่านิดหน่อย</p> <div class="course-tip bg-gradient-to-br dark:bg-gradient-to-r before:border-green-500 dark:before:border-green-800 from-green-50 dark:from-gray-900 to-white dark:to-gray-950 border border-green-50 text-green-700 dark:text-gray-400"><p data-svelte-h="svelte-1cne6h1">💡 ถ้าคุณใช้ <code>train_new_from_iterator()</code> กับ corpus ตัวอย่างนี้ คุณอาจจะไม่ได้ vocabulary เดียวกัน นั่นก็เพราะ 🤗 Tokenizers library ไม่ได้ใช้ WordPiece ในการเทรน แต่เราใช้ BPE</p></div> <p data-svelte-h="svelte-1ly7aaz">เมื่อคุณต้องการ tokenize ข้อความใหม่ คุณจะต้องทำการ pre-tokenize ข้อความแล้วจากนั้นจึง tokenize แต่ละคำ ตามหลักการของอัลกอริทึมนี้
	เราจะมองหาคำย่อยที่ยาวที่สุด โดยอ่านจากข้างหน้าคำไปข้างหลัง จากนั้นเราจะแยกคำหลักออกตรงคำย่อยนี้ จากนั้นทำขั้นตอนนี้ซ้ำกับส่วนต่อๆไปของคำนั้น แล้วทำเช่นเดียวกันกับคำต่อไป</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-keyword">def</span> <span class="hljs-title function_">encode_word</span>(<span class="hljs-params">word</span>):
	tokens = []
	<span class="hljs-keyword">while</span> <span class="hljs-built_in">len</span>(word) > <span class="hljs-number">0</span>:
	i = <span class="hljs-built_in">len</span>(word)
	<span class="hljs-keyword">while</span> i > <span class="hljs-number">0</span> <span class="hljs-keyword">and</span> word[:i] <span class="hljs-keyword">not</span> <span class="hljs-keyword">in</span> vocab:
	i -= <span class="hljs-number">1</span>
	<span class="hljs-keyword">if</span> i == <span class="hljs-number">0</span>:
	<span class="hljs-keyword">return</span> [<span class="hljs-string">"[UNK]"</span>]
	tokens.append(word[:i])
	word = word[i:]
	<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(word) > <span class="hljs-number">0</span>:
	word = <span class="hljs-string">f"##<span class="hljs-subst">{word}</span>"</span>
	<span class="hljs-keyword">return</span> tokens<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1w7dq7q">มาทดลอง tokenize คำที่มีใน vocabulary และอีกคำที่ไม่ได้อยู่ใน vocabulary กัน :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-built_in">print</span>(encode_word(<span class="hljs-string">"Hugging"</span>))
	<span class="hljs-built_in">print</span>(encode_word(<span class="hljs-string">"HOgging"</span>))<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->[<span class="hljs-string">'Hugg'</span>, <span class="hljs-string">'##i'</span>, <span class="hljs-string">'##n'</span>, <span class="hljs-string">'##g'</span>]
	[<span class="hljs-string">'[UNK]'</span>]<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-129ztod">ตอนนี้เราจะต้องเขียนฟังก์ชันเพื่อ tokenize ข้อความกัน :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --><span class="hljs-keyword">def</span> <span class="hljs-title function_">tokenize</span>(<span class="hljs-params">text</span>):
	pre_tokenize_result = tokenizer._tokenizer.pre_tokenizer.pre_tokenize_str(text)
	pre_tokenized_text = [word <span class="hljs-keyword">for</span> word, offset <span class="hljs-keyword">in</span> pre_tokenize_result]
	encoded_words = [encode_word(word) <span class="hljs-keyword">for</span> word <span class="hljs-keyword">in</span> pre_tokenized_text]
	<span class="hljs-keyword">return</span> <span class="hljs-built_in">sum</span>(encoded_words, [])<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-vjr41s">ทดลองฟังก์ชันของเรากับประโยคตัวอย่าง :</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->tokenize(<span class="hljs-string">"This is the Hugging Face course!"</span>)<!-- HTML_TAG_END --></pre></div> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->[<span class="hljs-string">'Th'</span>, <span class="hljs-string">'##i'</span>, <span class="hljs-string">'##s'</span>, <span class="hljs-string">'is'</span>, <span class="hljs-string">'th'</span>, <span class="hljs-string">'##e'</span>, <span class="hljs-string">'Hugg'</span>, <span class="hljs-string">'##i'</span>, <span class="hljs-string">'##n'</span>, <span class="hljs-string">'##g'</span>, <span class="hljs-string">'Fac'</span>, <span class="hljs-string">'##e'</span>, <span class="hljs-string">'c'</span>, <span class="hljs-string">'##o'</span>, <span class="hljs-string">'##u'</span>, <span class="hljs-string">'##r'</span>, <span class="hljs-string">'##s'</span>,
	<span class="hljs-string">'##e'</span>, <span class="hljs-string">'[UNK]'</span>]<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-15tnoli">นี่คือทั้งหมดเกี่ยวกับ WordPiece ในบทถัดไปเราจะมาเรียนเกี่ยวกับ Unigram กัน</p> <a class="!text-gray-400 !no-underline text-sm flex items-center not-prose mt-4" href="https://github.com/huggingface/course/blob/main/chapters/th/chapter6/6.mdx" target="_blank"><span data-svelte-h="svelte-1kd6by1"><</span> <span data-svelte-h="svelte-x0xyl0">></span> <span data-svelte-h="svelte-1dajgef"><span class="underline ml-1.5">Update</span> on GitHub</span></a> <p></p>

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