title stringlengths 12 150 | question_id int64 469 40.1M | question_score int64 2 5.52k | question_date stringdate 2008-08-02 15:11:16 2016-10-18 06:16:31 | answer_id int64 536 40.1M | answer_score int64 7 8.38k | answer_date stringdate 2008-08-02 18:49:07 2016-10-18 06:19:33 | tags listlengths 1 5 | question_body_md stringlengths 15 30.2k | answer_body_md stringlengths 11 27.8k |
|---|---|---|---|---|---|---|---|---|---|
is Python list comprehension with access to the index/enumerate possible? | 14,864,922 | 29 | 2013-02-13T22:59:56Z | 14,864,942 | 15 | 2013-02-13T23:02:19Z | [
"python",
"list",
"indexing",
"list-comprehension"
] | consider the following Python code with which I add in a new list2 all the items with indices from 1 to 3 of list1:
```
for ind, obj in enumerate(list1):
if 4> ind > 0: list2.append(obj)
```
how would you write this using python list comprehension, if I have no access to the indices through enumerate?
something ... | If you use `enumerate`, you *do* have access to the index:
```
list2 = [x for ind, x in enumerate(list1) if 4>ind>0]
``` |
Python module won't install | 14,865,990 | 11 | 2013-02-14T00:46:34Z | 14,867,310 | 12 | 2013-02-14T03:26:26Z | [
"python",
"setuptools",
"distutils"
] | This is my `setup.py` file
```
#!/usr/bin/env python
from setuptools import setup
from sys import path
setup(name= 'conundrum',
version= '0.1.0',
author= 'elssar',
author_email= 'elssar@altrawcode.com',
py_modules= ['conundrum'],
url= 'https://github.com/elssar/conundrum',
license= 'MIT',
... | I cannot run `setup.py` from a different directory. It needs to be run from the directory it is in. That was the problem here.
Fixed. |
Combining Grid search and cross validation in scikit learn | 14,866,228 | 9 | 2013-02-14T01:11:00Z | 14,872,267 | 12 | 2013-02-14T10:06:26Z | [
"python",
"svm",
"scikit-learn",
"cross-validation"
] | For improving Support Vector Machine outcomes i have to use grid search for searching better parameters and cross validation.
I'm not sure how combining them in scikit-learn.
Grid search search best parameters (<http://scikit-learn.org/stable/modules/grid_search.html>) and cross validation avoid overfitting (<http://sc... | You should do a development / evaluation split first, run the grid search on the development part and measure a unique final score on the evaluation part at the end:
There is [an example](http://scikit-learn.org/stable/auto_examples/model_selection/grid_search_digits.html) in [the documentation](http://scikit-learn.or... |
Update and create a multi-dimensional dictionary in Python | 14,867,496 | 6 | 2013-02-14T03:49:45Z | 14,867,580 | 10 | 2013-02-14T03:59:25Z | [
"python",
"dictionary",
"multidimensional-array"
] | I am parsing JSON that stores various code snippets and I am first building a dictionary of languages used by these snippets:
```
snippets = {'python': {}, 'text': {}, 'php': {}, 'js': {}}
```
Then when looping through the JSON I'm wanting add the information about the snippet into its own dictionary to the dictionar... | This is called [autovivification](http://en.wikipedia.org/wiki/Autovivification):
You can do it with `defaultdict`
```
def tree():
return collections.defaultdict(tree)
d = tree()
d['js']['title'] = 'Script1'
```
If the idea is to have lists, you can do:
```
d = collections.defaultdict(list)
d['js'].append({'fo... |
unittest for none type in python? | 14,868,170 | 6 | 2013-02-14T05:09:20Z | 21,715,451 | 11 | 2014-02-11T23:29:35Z | [
"python",
"unit-testing",
"assertion",
"nonetype"
] | I was just wondering how I would go about testing for a function that does not return anything. for example, say I have this function:
```
def is_in(char):
my_list = []
my_list.append(char)
```
and then if I were to test it:
```
class TestIsIn(unittest.TestCase):
def test_one(self):
''' Test if one ... | All Python functions return something. If you don't specify a return value, `None` is returned. So if your goal really is to make sure that something doesn't return a value, you can just say
```
self.assertIsNone(self.is_in('a'))
```
(However, this can't distinguish between a function without an explicit return value... |
Is there a way to convert pyplot.imshow() object to numpy array? | 14,869,321 | 2 | 2013-02-14T06:52:36Z | 14,877,059 | 7 | 2013-02-14T14:30:24Z | [
"python",
"opencv",
"numpy",
"matplotlib"
] | I need to visualize a 2D numpy array. I am using pyplot for this.
Here's the code:
```
import cv2 as cv
import numpy as np
from matplotlib import pyplot
img = pyplot.imshow( radiance_val )
#radiance_val is a 2D numpy array of size = ( 512, 512 )
#filled with np.float32 values
pyplot.show()
```
I am getting the out... | Unless you really need the marker ticks and such,
```
im._rgba_cache
```
gives you direct access to the MxNx4 `numpy` array that is the color mapped data.
If you just want the color mapped data, you can by pass `imshow` entirely and directly color-map the data your self (see [guide](http://matplotlib.org/users/color... |
Logical OR operation with -1 | 14,870,421 | 3 | 2013-02-14T08:14:18Z | 14,870,446 | 8 | 2013-02-14T08:16:00Z | [
"python",
"python-2.7",
"logical-operators"
] | Why is the output different for the following logical operations that I tried in python?
```
-1 or 1
1 or -1
```
First returns `-1` and second returns `1` | `and` and `or` are both *lazy*; they evaluate operands until they can decide the result (`and` stops at the first `False` operand; `or` stops at the first `True` operand). They return the last operand evaluated, as noted in [the documentation](http://docs.python.org/2/reference/expressions.html#boolean-operations):
> ... |
Logical OR operation with -1 | 14,870,421 | 3 | 2013-02-14T08:14:18Z | 14,870,451 | 7 | 2013-02-14T08:16:05Z | [
"python",
"python-2.7",
"logical-operators"
] | Why is the output different for the following logical operations that I tried in python?
```
-1 or 1
1 or -1
```
First returns `-1` and second returns `1` | Read [the documentation](http://docs.python.org/3/reference/expressions.html#boolean-operations):
> The expression `x or y` first evaluates `x`; if `x` is true, its value is returned; otherwise, `y` is evaluated and the resulting value is returned. |
py2exe: error: libzmq.pyd: No such file or directory | 14,870,825 | 4 | 2013-02-14T08:43:57Z | 23,179,471 | 8 | 2014-04-20T07:07:23Z | [
"python",
"py2exe",
"pyzmq"
] | During py2exe build I get the following error:
```
creating python loader for extension 'win32clipboard' (C:\Python27\lib\site-packages\win32\win32clipboard.pyd -> win32clipboard.pyd)
creating python loader for extension '_rl_accel' (C:\Python27\lib\site-packages\_rl_accel.pyd -> _rl_accel.pyd)
*** finding dlls needed... | Three steps are necessary to make it work:
* Exclude `libzmq.pyd` from dlls with `dll_excludes` option. This avoids "missing pyzmq.pyd" errors.
* Exclude `zmq.libzmq` (same thing) from modules with `excludes`. This skips the usual .pyd renamind and proxying that py2exe does.
* Add `zmq.backend.cython` explicitly with ... |
Deleting variables in Python standard libraries | 14,871,275 | 6 | 2013-02-14T09:12:53Z | 14,871,298 | 8 | 2013-02-14T09:14:03Z | [
"python",
"reference",
"try-catch"
] | I've been reading some of the code in a standard *threading* library ( Python 2.6 ) and there was a piece of code which made me wonder. It can be shorten to the following structure ( compare to \_\_bootstrap\_inner method in *threading.py* ):
```
def foo():
exc_type, exc_value, exc_tb = sys.exc_info()
try:
... | Yes, at the very least for `exc_tb`; traceback objects hold a reference to the current frame, and that makes this a circular reference.
By deleting the local reference you break that circle, so you don't have to hope and trust that the garbage collector will be able to.
From the [`sys.exc_info()` function docs](http:... |
Find element in list | 14,872,046 | 2 | 2013-02-14T09:54:43Z | 14,872,113 | 9 | 2013-02-14T09:58:19Z | [
"python",
"list"
] | I have a list like
```
list_a = [(1, 2), (2, 3), (4, 5)]
```
and now using this list i wanted to find a element which has last value 3 any short method to achieve this? it should return `(2,3)` | For example:
```
In [1]: list_a = [(1, 2), (2, 3), (4, 5)]
In [2]: next(x for x in list_a if x[1] == 3)
Out[2]: (2, 3)
```
Note that it returns a single element, not a list of them (seems to be what you are asking). If there are multiple tuples, the first one is returned. |
Get IP Address when testing flask application through nosetests | 14,872,829 | 11 | 2013-02-14T10:35:25Z | 14,873,034 | 16 | 2013-02-14T10:46:21Z | [
"python",
"testing",
"flask",
"nosetests",
"werkzeug"
] | My application depends on `request.remote_addr` which is `None` when i run tests through nosetests which uses `app.test_client().post('/users/login', ....)`.
**How can I emulate an IP (127.0.0.1 works fine) when I run tests?**
I've tried setting environment variables, sent in headers with the post() method and I've di... | You can set options for the underlying Werkzeug environment using [environ\_base](http://werkzeug.pocoo.org/docs/test/#testing-api):
```
from flask import Flask, request
import unittest
app = Flask(__name__)
app.debug = True
app.testing = True
@app.route('/')
def index():
return str(request.remote_addr)
class T... |
Plotting of 1-dimensional Gaussian distribution function | 14,873,203 | 6 | 2013-02-14T10:56:01Z | 14,880,001 | 11 | 2013-02-14T16:54:43Z | [
"python",
"plot",
"gaussian"
] | How do I make plots of a 1-dimensional Gaussian distribution function using the mean and standard deviation parameter values (μ, Ï) = (â1, 1), (0, 2), and (2, 3)?
I'm new to programming, using Python.
Thank you in advance! | With the excellent `matplotlib` and `numpy` packages
```
from matplotlib import pyplot as mp
import numpy as np
def gaussian(x, mu, sig):
return np.exp(-np.power(x - mu, 2.) / (2 * np.power(sig, 2.)))
for mu, sig in [(-1, 1), (0, 2), (2, 3)]:
mp.plot(gaussian(np.linspace(-3, 3, 120), mu, sig))
mp.show()
```... |
Plotting of 1-dimensional Gaussian distribution function | 14,873,203 | 6 | 2013-02-14T10:56:01Z | 17,331,318 | 8 | 2013-06-26T22:07:21Z | [
"python",
"plot",
"gaussian"
] | How do I make plots of a 1-dimensional Gaussian distribution function using the mean and standard deviation parameter values (μ, Ï) = (â1, 1), (0, 2), and (2, 3)?
I'm new to programming, using Python.
Thank you in advance! | You are missing a parantheses in the denominator of your gaussian() function. As it is right now you divide by 2 and multiply with the variance (sig^2). But that is not true and as you can see of your plots the greater variance the more narrow the gaussian is - which is wrong, it should be opposit.
So just change the ... |
apscheduler in Flask executes twice | 14,874,782 | 20 | 2013-02-14T12:22:32Z | 15,491,587 | 20 | 2013-03-19T04:38:34Z | [
"python",
"flask",
"apscheduler"
] | I have problem when i am using apscheduler in my flask application.
In my view.py file i am writing like this
```
import time
from apscheduler.scheduler import Scheduler
def test_scheduler():
print "TEST"
print time.time()
sched = Scheduler()
sched.add_interval_job(test_scheduler, seconds=5)
sched.start(... | In debug mode, Flask's reloader will load the flask app twice ([How to stop flask from initialising twice in Debug Mode?](http://stackoverflow.com/questions/9449101/how-to-stop-flask-from-initialising-twice-in-debug-mode)). I'm not sure why this is, but it causes apscheduler's jobs to be scheduled twice. A quick `print... |
Readonly text field in Flask-Admin ModelView | 14,874,846 | 5 | 2013-02-14T12:25:57Z | 18,839,552 | 11 | 2013-09-17T00:40:42Z | [
"python",
"flask",
"flask-sqlalchemy",
"flask-admin"
] | How can I make a field on a `ModelView` readonly?
```
class MyModelView(BaseModelView):
column_list = ('name', 'last_name', 'email')
``` | If you're talking about Flask-Admin with SQLAlchemy Models, and you're declaring a view by inheriting from sqlamodel.ModelView, you can just add this to your class definition:
```
class MyModelView(BaseModelView):
column_list = ('name', 'last_name', 'email')
form_widget_args = {
'email':{
'... |
Python, numpy sort array | 14,875,248 | 3 | 2013-02-14T12:50:36Z | 14,875,366 | 20 | 2013-02-14T12:57:06Z | [
"python",
"numpy"
] | I'am using numpy and have an array (ndarray type) which contain some values. Shape of this array 1000x1500. I reshaped it
```
brr = np.reshape(arr, arr.shape[0]*arr.shape[1])
```
when I trying
```
brr.reverse()
AttributeError: ânumpy.ndarrayâ object has no attribute âreverseâ
```
get error.
How I can sort t... | If you just want to reverse it:
```
brr[:] = brr[::-1]
```
Actually, this reverses along axis 0. You could also revert on any other axis, if the array has more than one.
To sort in reverse order:
```
>>> arr = np.random.random((1000,1500))
>>> brr = np.reshape(arr, arr.shape[0]*arr.shape[1])
>>> brr.sort()
>>> brr ... |
Duplicate element in python list | 14,878,538 | 9 | 2013-02-14T15:42:16Z | 14,878,621 | 15 | 2013-02-14T15:46:00Z | [
"python",
"list",
"list-comprehension"
] | I have a `list` in Python:
```
l = ['a', 'c', 'e', 'b']
```
I want to duplicate each element immediately next to the original.
```
ll = ['a', 'a', 'c', 'c', 'e', 'e', 'b', 'b']
```
The order of the elements should be preserved. | ```
>>> l = ['a', 'c', 'e', 'b']
>>> [x for pair in zip(l,l) for x in pair]
['a', 'a', 'c', 'c', 'e', 'e', 'b', 'b']
```
Or
```
>>> from itertools import repeat
>>> [x for item in l for x in repeat(item, 2)]
['a', 'a', 'c', 'c', 'e', 'e', 'b', 'b']
``` |
Merge xml files with nested elements without external libraries | 14,878,706 | 11 | 2013-02-14T15:51:02Z | 14,879,370 | 16 | 2013-02-14T16:23:46Z | [
"python",
"xml",
"python-2.7",
"elementtree"
] | I am trying to merge multiple XML files together using Python and no external libraries. The XML files have nested elements.
**Sample File 1:**
```
<root>
<element1>textA</element1>
<elements>
<nested1>text now</nested1>
</elements>
</root>
```
**Sample File 2:**
```
<root>
<element2>textB</element2>
... | What the code you posted is doing is combining all the elements regardless of whether or not an element with the same tag already exists. So you need to iterate over the elements and manually check and combine them the way you see fit, because it is not a standard way of handling XML files. I can't explain it better th... |
Iterate a list of tuples | 14,880,192 | 9 | 2013-02-14T17:05:31Z | 14,880,267 | 22 | 2013-02-14T17:09:59Z | [
"python",
"list",
"iteration",
"tuples"
] | I'm looking for a clean way to iterate over a list of tuples where each is a pair like so `[(a, b), (c,d) ...]`. On top of that I would like to alter the tuples in the list.
Standard practice is to avoid changing a list while also iterating through it, so what should I do? Here's what I kind of want:
```
for i in ran... | Just replace the tuples in the list; you *can* alter a list while looping over it, as long as you avoid adding or removing elements:
```
for i, (a, b) in enumerate(tuple_list):
new_b = some_process(b)
tuple_list[i] = (a, new_b)
```
or, if you can summarize the changes to `b` into a function as I did above, us... |
Why do some Python functions have an extra set of parenthesis around the argument list? | 14,880,406 | 9 | 2013-02-14T17:17:48Z | 14,880,436 | 10 | 2013-02-14T17:18:50Z | [
"python",
"arguments",
"parentheses"
] | I've seen some Python functions written like this:
```
def get_year((year,prefix,index,suffix)):
return year
```
How does that differ (if at all) from other functions without the extra parentheses like this:
```
def do_format(yr,pfx,id,sfx):
return "%s %s %s/%s"%(yr, id, pfx, sfx)
```
Or is it just a matter of ... | The first function takes a single tuple argument, whereas the second function takes 4 arguments. You can pass those parameters individually, or as a tuple with `splat` operator, that will unpack the tuple into individual parameters.
E.g:
```
# Valid Invocations
print do_format(*('2001', '234', '12', '123')) # Tuple ... |
Encoding on PostgreSQL, Python, Jinja2 | 14,881,467 | 4 | 2013-02-14T18:21:16Z | 14,887,474 | 7 | 2013-02-15T02:25:24Z | [
"python",
"encoding",
"utf-8",
"flask",
"jinja2"
] | I'm having a problem with encoding in my application and didn't find the solution anywhere on web.
Here is the scenario:
* PostgreSQL with UTF-8 encoding (`CREATE DATABASE xxxx WITH ENCODING 'UTF8'`)
* Python logic also with UTF-8 encoding (`# -*- coding: utf-8 -*-`)
* Jinja2 to show my HTML pages. Python and Jinja2 ... | The issue is that [psycopg2 returns *byte strings* by default in Python 2](http://initd.org/psycopg/docs/usage.html#unicode-handling):
> When reading data from the database, in Python 2 the strings returned are usually 8 bit `str` objects encoded in the database client encoding
So you can either:
* Manually decode a... |
rpy2 install on windows 7 | 14,882,477 | 13 | 2013-02-14T19:24:15Z | 25,630,406 | 10 | 2014-09-02T18:57:49Z | [
"python",
"windows",
"install",
"rpy2"
] | I'm trying to install rpy2 on my computer, but I wasn't able to do it.
I downloaded the source package and I tryed to install Rpy2 (rpy2-2.3.2) using the command `python setup.py install`. This is the result:
```
running install
running build
running build_py
running build_ext
"C:\PROGRA~1\R\R-215~1.2\bin\R" CMD conf... | I just successfully installed rpy2 on Windows 8.1 64bit with the binary installer from <http://www.lfd.uci.edu/~gohlke/pythonlibs/#rpy2>. It is usually much easier to just download a binary instead of trying to compile a package in Windows.
Also, you should set `R_HOME` environmental variable (in my case, to `C:\Progr... |
How should I establish and manage database connections in a multi-module Python app? | 14,883,346 | 8 | 2013-02-14T20:20:55Z | 14,883,590 | 7 | 2013-02-14T20:37:55Z | [
"python",
"mysql"
] | We have a Python application with over twenty modules, most of which are shared by several web and console applications.
I've never had a clear understanding of the best practice for establishing and managing database connection in multi module Python apps. Consider this example:
I have a module defining an object cl... | The best method is to open a connection when you need to do some operations (like getting and/or updating data); manipulate the data; write it back to the database in **one query** (very important for performance), and then close the connection. Opening a connection is a fairly light process.
Some pitfalls for perform... |
How to calculate moving average in Python 3? | 14,884,017 | 4 | 2013-02-14T21:05:19Z | 14,884,062 | 13 | 2013-02-14T21:07:58Z | [
"python",
"python-3.x"
] | Let's say I have a list:
```
y = ['1', '2', '3', '4','5','6','7','8','9','10']
```
I want to create a function that calculates the moving n-day average.
So if `n` was 5, I would want my code to calculate the first 1-5, add it and find the average, which would be 3.0, then go on to 2-6, calculate the average, which wo... | There is a great sliding window generator in an old version of the Python docs with [`itertools` examples](http://docs.python.org/release/2.3.5/lib/itertools-example.html):
```
from itertools import islice
def window(seq, n=2):
"Returns a sliding window (of width n) over data from the iterable"
" s -> (s0,s... |
Incorrect string value warning when calling stored procedure in python | 14,884,358 | 4 | 2013-02-14T21:28:16Z | 14,884,915 | 8 | 2013-02-14T22:04:41Z | [
"python",
"mysql",
"stored-procedures",
"utf-8",
"mysql-python"
] | I have a database that has a stored procedure that I call it in my python script.
until yesterday there were no problem with it.
but yesterday my database server had a problem and restored the database.
now I'm getting this warning from the same code:
```
Warning: Incorrect string value: '\xD9\x88\xD8\xB2\xDB\x8... | Problem solved!
I added `CHARACTER SET utf8` to my stored procedure's VARCHAR arguments and problem solved:
```
..., IN `title` VARCHAR(255) CHARSET utf8,...
```
But yet I wonder why before restoring DB there was no problem !!!??? |
Max/Min value of Dictionary of List | 14,884,376 | 3 | 2013-02-14T21:29:04Z | 14,884,421 | 8 | 2013-02-14T21:32:21Z | [
"python"
] | I have a dictionary mapping an id\_ to a list of data values like so: `dic = {id_ : [v1, v2, v3, v4]}`.
I'm trying to iterate through every value in the dictionary and retrieve the max/min of a certain index of the list mappings.
What I want to do is something like this:
```
maximum = max([data[0], ??) for id_, data ... | You need to use it something like this:
```
maximum = max(data[0] for data in dic.values())
```
since you are not using your `keys`, simply use `dict.values()` to get just the values. |
Django 1.4 Unknown command: 'runserver' | 14,885,299 | 10 | 2013-02-14T22:31:47Z | 14,900,746 | 18 | 2013-02-15T18:08:39Z | [
"python",
"django",
"python-2.7"
] | Something in my python path must have changed because now I cannot run the.
```
python app/manage.py runserver
```
The output I get is
```
Unknown command: 'runserver'
Type 'manage.py help' for usage.
```
I've looked at my environment's PYTHONPATH and PATH variables, but I can't figure out why its not running. | I've found the answer to my question.
* If you've got an error in your settings, manage.py will swallow the exception and report as if the command does not exist.
* This lead me down the path of incorrectly assuming my python path or venv environment was messed up.
If you want to diagnose this issue, run...
```
pyth... |
What is needed to use gdb 7's support for debugging Python programs? | 14,885,328 | 10 | 2013-02-14T22:33:55Z | 14,905,356 | 14 | 2013-02-16T00:01:39Z | [
"python",
"debugging",
"ubuntu",
"gdb",
"centos"
] | I'd like to use gdb 7's support for debugging Python "inferior processes".
What do I need to be able to do that?
For example:
* What flags does the inferior Python's configure script need to have been run with?
* Does the inferior Python process have to be Python 2.7 or newer (I see that's when the part of the gdb s... | Python seems to need to have been compiled with `--with-pydebug` (on Ubuntu 12.04, package `python-dbg` contains a suitable Python executable, itself called `python-dbg`). The inferior Python does not need to be Python 2.7 -- 2.6 loads the 2.7 gdb extensions successfully (see the debugging session below). At least on U... |
How to implement a particle engine | 14,885,349 | 5 | 2013-02-14T22:35:25Z | 14,892,607 | 12 | 2013-02-15T10:23:22Z | [
"python",
"refactoring",
"pygame",
"particle-system"
] | So I have made a particle engine for smoke that I'm pretty happy with I think it fits my game pretty well.
I now need to implement it into my game and I'm having a little bit of trouble. I was wondering if someone could explain how I would go about using my particle engine in my game.
I added the both my codes(for ... | Beware! Long post!
## The particle
First, let's take a look at your `Smoke` class. It contains some of the *smoke* behaviour, but also your main loop does. Let's fix that by creating a generic `Particle` class that does nothing but represent a particle:
```
class Particle():
def __init__(self, col, size, *strate... |
strip white spaces from file csv | 14,885,908 | 13 | 2013-02-14T23:24:48Z | 17,117,621 | 16 | 2013-06-14T21:34:22Z | [
"python",
"csv"
] | I need to stripe the white spaces from a csv file that i read
import csv
```
aList=[]
with open(self.filename, 'r') as f:
reader = csv.reader(f, delimiter=',', quoting=csv.QUOTE_NONE)
for row in reader:
aList.append(row)
# i need to strip the extra white space from each string in the row
return... | There's also the embedded formatting parameter: skipinitialspace (the default is false)
<http://docs.python.org/2/library/csv.html#csv-fmt-params>
```
aList=[]
with open(self.filename, 'r') as f:
reader = csv.reader(f, skipinitialspace=False,delimiter=',', quoting=csv.QUOTE_NONE)
for row in reader:
aLi... |
Python import module from sibling folder | 14,886,143 | 12 | 2013-02-14T23:48:39Z | 14,886,199 | 9 | 2013-02-14T23:53:04Z | [
"python",
"import",
"module",
"relative"
] | I have gone through many Python relative import questions but I can't understand the issue/get it to work...
My Directory structure is:
```
Driver.py
A/
Account.py
__init__.py
B/
Test.py
__init__.py
```
====================
Driver.py
```
from B import Test
```
=========
Account.py
```
... | This is happening because `A` and `B` are independent, unrelated, packages as far as Python is concerned.
Create a `__init__.py` in the same directory as `Driver.py` and everything should work as expected. |
"Unorderable types: int() < str()" | 14,886,881 | 11 | 2013-02-15T01:08:18Z | 14,886,894 | 17 | 2013-02-15T01:09:28Z | [
"python",
"calculator"
] | Hey guys so I'm trying to make a retirement calculator right now on Python. There's nothing wrong with the syntax but when I run the following program:
```
def main():
print("Let me Retire Financial Calculator")
deposit = input("Please input annual deposit in dollars: $")
rate = input ("Please input annual... | The issue here is that `input()` returns a string in Python 3.x, so when you do your comparison, you are comparing a string and an integer, which isn't well defined (what if the string is a word, how does one compare a string and a number?) - in this case Python doesn't guess, it throws an error.
To fix this, simply c... |
How to return array from C++ function to Python using ctypes | 14,887,378 | 10 | 2013-02-15T02:09:58Z | 14,887,649 | 8 | 2013-02-15T02:56:40Z | [
"c++",
"python",
"arrays",
"return",
"ctypes"
] | I am using ctypes to implement a C++ function in Python. The C++ function should return a pointer to an array. Unfortunately I haven't figured out, how to access the array in Python. I tried numpy.frombuffer, but that was not successful. It just returned an array of arbitrary numbers. Obviously I didn't used it correct... | `function.cpp` returns an int array, while `wrapper.py` tries to interpret them as doubles. Change `ArrayType` to `ctypes.c_int * 10` and it should work.
---
It's probably easier to just use [`np.ctypeslib`](http://docs.scipy.org/doc/numpy/reference/routines.ctypeslib.html) instead of `frombuffer` yourself. This shou... |
How to return array from C++ function to Python using ctypes | 14,887,378 | 10 | 2013-02-15T02:09:58Z | 14,892,980 | 16 | 2013-02-15T10:45:28Z | [
"c++",
"python",
"arrays",
"return",
"ctypes"
] | I am using ctypes to implement a C++ function in Python. The C++ function should return a pointer to an array. Unfortunately I haven't figured out, how to access the array in Python. I tried numpy.frombuffer, but that was not successful. It just returned an array of arbitrary numbers. Obviously I didn't used it correct... | Your python code will work after some minor modifications:
```
import ctypes
f = ctypes.CDLL('./library.so').function
f.restype = ctypes.POINTER(ctypes.c_int * 10)
print [i for i in f().contents] # output: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
```
Basically there are two changes:
1. remove numpy-related code and `ctypes.c... |
python pandas DataFrame subplot in columns and rows | 14,888,473 | 11 | 2013-02-15T04:54:57Z | 17,106,156 | 9 | 2013-06-14T10:13:23Z | [
"python",
"dataframe",
"pandas",
"subplot"
] | I would like to produce a subplot from data 4 column DataFrame into 2 rows and 2 columns
```
df =pd.DataFrame(np.random.randn(6,4),index=pd.date_range('1/1/2000',periods=6, freq='1h'))
```
However below will give a 4 row and 1 column plot
```
df.plot(use_index=False, title=f, subplots=True, sharey=True, figsize=(8,... | cplcloud's answer works, but following code will give you a bit more structure so that you can start configuring more if you do not need the loop.
```
fig, axes = plt.subplots(nrows=2, ncols=2)
fig.set_figheight(6)
fig.set_figwidth(8)
df[0].plot(ax=axes[0,0], style='r', label='Series'); axes[0,0].set_title(0)
df[1].pl... |
Disable console messages in Flask server | 14,888,799 | 25 | 2013-02-15T05:29:24Z | 18,379,764 | 36 | 2013-08-22T11:57:07Z | [
"python",
"flask"
] | I have a Flask server running in standalone mode (using `app.run()`). But, I don't want any messages in the console, like
```
127.0.0.1 - - [15/Feb/2013 10:52:22] "GET /index.html HTTP/1.1" 200 -
...
```
How do I disable verbose mode? | You can set set level of the Werkzeug logger to ERROR, in that case only errors are logged:
```
import logging
log = logging.getLogger('werkzeug')
log.setLevel(logging.ERROR)
```
Here are a full working example testet on OSX, Python 2.7.5, Flask 0.10.0:
```
from flask import Flask
app = Flask(__name__)
import loggi... |
Django : <django.utils.functional.__proxy__ object at 0x7feaac2761d0> is not JSON serializable | 14,890,263 | 8 | 2013-02-15T07:49:45Z | 16,003,647 | 17 | 2013-04-14T19:55:21Z | [
"python",
"django",
"serialization"
] | I am getting a problem in django serialization
Here is my model for the state
```
class State(models.Model):
class Translation(translation.Translation):
name = models.CharField(max_length=64)
capital = models.ForeignKey('City', related_name="state_capital", null=True)
country = models.For... | `django.utils.functional.__proxy__` object is a lazy translation. Django documentation says that calling unicode() with the lazy translation as the argument will generate a Unicode string in the current locale (<https://docs.djangoproject.com/en/dev/ref/unicode/#translated-strings>). When the translation is done, seria... |
Installing PocketSphinx on a MAC OS X | 14,890,546 | 6 | 2013-02-15T08:15:29Z | 14,890,599 | 12 | 2013-02-15T08:19:30Z | [
"python",
"osx",
"cmusphinx",
"sphinx4"
] | I'm trying to learn pocketsphinx using python, and therefore wanted to install the same on my Mac OSX Lion. However, I'm really not experienced with installing packages and modules in Python, and the documentation on this one is slightly confusing for me.
Here's what I've done till now. I downloaded the pocketsphinx 0.... | There is a [homebrew formula](https://github.com/mxcl/homebrew/blob/master/Library/Formula/cmu-pocketsphinx.rb) for pocketsphinx, which (just) installed fine on my system (Mountain Lion). Maybe try that? `brew install cmu-pocketsphinx` worked for me... |
Passing arguments into os.system | 14,892,355 | 3 | 2013-02-15T10:11:00Z | 14,892,402 | 7 | 2013-02-15T10:13:37Z | [
"python",
"argparse",
"os.system"
] | I need to execute the following command through python. rtl2gds is a tool which reads in 2 parameters: Path to a file and a module name
```
rtl2gds -rtl=/home/users/name/file.v -rtl_top=module_name -syn
```
I am reading in the path to the file and module name from the user through argparse as shown below:
```
parser... | Don't use `os.system()`; `subprocess` is definitely the way to go.
Your problem though is that you expect Python to understand that you want to interpolate `args.fileread` into a string. As great as Python is, it is not able to read your mind like that!
Use string formatting instead:
```
os.system("rtl2gds -rtl={arg... |
How do you load .ui files onto python classes with PySide? | 14,892,713 | 14 | 2013-02-15T10:29:12Z | 14,894,550 | 18 | 2013-02-15T12:14:43Z | [
"python",
"qt",
"user-interface",
"pyqt",
"pyside"
] | I've used PyQt for quite a while, and the entire time I've used it, there has been a pretty consistent programming pattern.
1. Use Qt Designer to create a .ui file.
2. Create a python class of the same type as the widget you created in the .ui file.
3. When initializing the python class, use uic to dynamically load th... | I'm doing exactly that with PySide. :)
You use this <https://gist.github.com/cpbotha/1b42a20c8f3eb9bb7cb8> (original by Sebastian Wiesner was at <https://github.com/lunaryorn/snippets/blob/master/qt4/designer/pyside_dynamic.py> but has disappeared) - which overrides PySide.QtUiTools.QUiLoader and supplies a new `loadU... |
Running windows shell commands with python | 14,894,993 | 14 | 2013-02-15T11:29:43Z | 14,898,162 | 28 | 2013-02-15T15:41:09Z | [
"python",
"windows",
"operating-system",
"shell"
] | How can we interact with OS shell using Python ?
I want to run windows cmd commands via python. How can it be achieved ? | The newer `subprocess.check_output` and similar commands are supposed to replace `os.system`. See [this page](http://docs.python.org/2/library/subprocess.html) for details. While I can't test this on Windows, the following should work:
```
from subprocess import check_output
check_output("dir C:", shell=True)
```
`ch... |
Insert an element at specific index in a list and return updated list | 14,895,599 | 24 | 2013-02-15T13:16:03Z | 14,895,600 | 10 | 2013-02-15T13:16:03Z | [
"python",
"list",
"python-2.7"
] | I have this:
```
>>> a = [1, 2, 4]
>>> print a
[1, 2, 4]
>>> print a.insert(2, 3)
None
>>> print a
[1, 2, 3, 4]
>>> b = a.insert(3, 6)
>>> print b
None
>>> print a
[1, 2, 3, 6, 4]
>>>
```
Is there anyway I can get the updated list as result, instead of updating the original list in place? | Shortest I got: `b = a[:2] + [3] + a[2:]`
```
>>>
>>> a = [1, 2, 4]
>>> print a
[1, 2, 4]
>>> b = a[:2] + [3] + a[2:]
>>> print a
[1, 2, 4]
>>> print b
[1, 2, 3, 4]
``` |
Insert an element at specific index in a list and return updated list | 14,895,599 | 24 | 2013-02-15T13:16:03Z | 14,895,767 | 19 | 2013-02-15T13:23:50Z | [
"python",
"list",
"python-2.7"
] | I have this:
```
>>> a = [1, 2, 4]
>>> print a
[1, 2, 4]
>>> print a.insert(2, 3)
None
>>> print a
[1, 2, 3, 4]
>>> b = a.insert(3, 6)
>>> print b
None
>>> print a
[1, 2, 3, 6, 4]
>>>
```
Is there anyway I can get the updated list as result, instead of updating the original list in place? | `l.insert(index, obj)` doesn't actually return anything, it just updates the list.
As ATO said, you can do `b = a[:index] + [obj] + a[index:]`.
However, another way is:
```
a = [1, 2, 4]
a.insert(2, 3)
b = a[:]
``` |
Django remove unicode in values_list | 14,895,981 | 6 | 2013-02-15T13:37:44Z | 14,896,038 | 12 | 2013-02-15T13:40:53Z | [
"python",
"django",
"django-views",
"django-queryset"
] | I did this operation:
```
definitions.objects.values_list('title', flat=True)
```
And it returns these results:
```
[u'accelerate', u'acute', u'bear', u'big'...]
```
You will realize that the results are all in unicode (u'). How do I remove them all so that I get the result:
```
['accelerate', 'acute', 'bear', 'bi... | If you want to encode in utf8, you can simply do:
```
definitions_list = [definition.encode("utf8") for definition in definitions.objects.values_list('title', flat=True)]
``` |
Get the inner HTML of a element in lxml | 14,896,302 | 10 | 2013-02-15T13:56:30Z | 14,896,448 | 18 | 2013-02-15T14:05:25Z | [
"python",
"xpath",
"lxml"
] | I am trying to get the HTML content of child node with lxml and xpath in Python. As shown in code below, I want to find the html content of the each of product nodes. Does it have any methods like product.html?
```
productGrids = tree.xpath("//div[@class='name']/parent::*")
for product in productGrids:
print #html... | ```
from lxml import etree
print(etree.tostring(root, pretty_print=True))
```
you may see more examples here: <http://lxml.de/tutorial.html> |
matplotlib hooking in to home/back/forward button events | 14,896,580 | 7 | 2013-02-15T14:12:44Z | 15,109,266 | 8 | 2013-02-27T10:06:06Z | [
"python",
"matplotlib"
] | Does anyone know how to 'get' the 'home', 'back' and 'forward' button events from a matplotlib figure?
I need the events to call some of my functions such that my plots behave correctly when those button are pressed, i.e. the default behaviour isn't doing what i need it to do
Matplotlib assumes the underlying dataset... | Matplotlib doesn't provide 'home', 'back' or 'forward' button event.
To add a callback that will be called with 'home', 'back' or 'forward' button event, a common approach is to subclass a matplotlib backend.
But I am not in favor of this approach. I think it has two cons:
1. If you want to use different backends,... |
Create multiple columns in pandas aggregation function | 14,897,100 | 7 | 2013-02-15T14:42:40Z | 14,906,226 | 8 | 2013-02-16T02:15:53Z | [
"python",
"pandas",
"time-series"
] | I'd like to create multiple columns while resampling a pandas DataFrame like the built-in ohlc method.
```
def mhl(data):
return pandas.Series([np.mean(data),np.max(data),np.min(data)],index = ['mean','high','low'])
ts.resample('30Min',how=mhl)
```
Dies with
```
Exception: Must produce aggregated value
```
Any... | You can pass a dictionary of functions to the `resample` method:
```
In [35]: ts
Out[35]:
2013-01-01 00:00:00 0
2013-01-01 00:15:00 1
2013-01-01 00:30:00 2
2013-01-01 00:45:00 3
2013-01-01 01:00:00 4
2013-01-01 01:15:00 5
...
2013-01-01 23:00:00 92
2013-01-01 23:15:00 93
2013-01-01 23:30:... |
What causes "no viable alternative at input 'None'" error with Cassandra CQL | 14,897,599 | 9 | 2013-02-15T15:10:56Z | 14,897,898 | 13 | 2013-02-15T15:27:42Z | [
"python",
"cassandra",
"cql"
] | I'm attempting to insert a modified document back to Cassandra DB with a new key. I'm having hard time figuring out what is the issue the error message is pointing at. When looking for others that have had similar problems the answers seem to be related to the keys, and in my case the None is just a value of few of the... | The "no viable alternative" means that the data type for some key doesn't match the schema for that column family column, unfortunately it doesn't plainly say that in the error message.
In my case the data type for meta was:
```
map<text,text>
```
for this reason None was considered a bad value at insertion time. I ... |
Python multiprocessing, ValueError: I/O operation on closed file | 14,899,355 | 3 | 2013-02-15T16:46:11Z | 14,899,817 | 7 | 2013-02-15T17:11:13Z | [
"python",
"file",
"multiprocessing"
] | I'm having a problem with the Python multiprocessing package. Below is a simple example code that illustrates my problem.
```
import multiprocessing as mp
import time
def test_file(f):
f.write("Testing...\n")
print f.name
return None
if __name__ == "__main__":
f = open("test.txt", 'w')
proc = mp.Process(ta... | I had similar issues in the past. Not sure whether it is done within the multiprocessing module or whether `open` sets the close-on-exec flag by default but I know for sure that file handles opened in the main process are *closed* in the multiprocessing children.
The obvious work around is to pass the filename as a pa... |
Displaying better error message than "No JSON object could be decoded" | 14,899,506 | 73 | 2013-02-15T16:54:12Z | 14,899,579 | 13 | 2013-02-15T16:58:05Z | [
"python",
"json"
] | Python code to load data from some long complicated JSON file:
```
with open(filename, "r") as f:
data = json.loads(f.read())
```
For many types of JSON error (missing delimiters, incorrect backslashes in strings, etc), this prints a nice helpful message containing the line and column number where the JSON error wa... | You wont be able to get python to tell you where the JSON is incorrect. You will need to use a linter online somewhere like [this](http://jsonformatter.curiousconcept.com/)
This will show you error in the JSON you are trying to decode. |
Displaying better error message than "No JSON object could be decoded" | 14,899,506 | 73 | 2013-02-15T16:54:12Z | 14,956,465 | 92 | 2013-02-19T11:33:45Z | [
"python",
"json"
] | Python code to load data from some long complicated JSON file:
```
with open(filename, "r") as f:
data = json.loads(f.read())
```
For many types of JSON error (missing delimiters, incorrect backslashes in strings, etc), this prints a nice helpful message containing the line and column number where the JSON error wa... | I've found that the `simplejson` module gives more descriptive errors in many cases where the built-in `json` module is vague. For instance, for the case of having a comma after the last item in a list:
```
json.loads('[1,2,]')
....
ValueError: No JSON object could be decoded
```
which is not very descriptive. The sa... |
format output data in pandas to_html | 14,899,818 | 3 | 2013-02-15T17:11:12Z | 14,899,978 | 7 | 2013-02-15T17:21:21Z | [
"python",
"pandas"
] | I use pandas' to\_html to generate output file, when data are written to the file they have many digits after the decimal point. The pandas' to\_html float\_format method can limit the digits, but when I used 'float\_format' as below:
```
DataFormat.to_html(header=True,index=False,na_rep='NaN',float_format='%10.2f')
`... | From the `to_html` docs:
```
float_format : one-parameter function, optional
formatter function to apply to columns' elements if they are floats
default None
```
You need to pass a function. For example:
```
>>> df = pd.DataFrame({"A": [1.0/3]})
>>> df
A
0 0.333333
>>> print df.to_html()
<table b... |
Plotting function that returns complex values using pyplot | 14,901,376 | 3 | 2013-02-15T18:48:20Z | 14,901,655 | 7 | 2013-02-15T19:09:19Z | [
"python",
"numpy",
"matplotlib",
"scipy"
] | I found this image on Facebook and wanted to plot it, as I thought it will be a good opportunity to learn something new.
The code:
```
import numpy as np
import scipy.special
import pylab
x = np.linspac... | ```
import matplotlib.pyplot as plt
import numpy as np
y, x = np.ogrid[-1:2:100j, -1:1:100j]
plt.contour(x.ravel(), y.ravel(), x**2 + (y-((x**2)**(1.0/3)))**2, [1])
plt.axis('equal')
plt.show()
```
---
You can play with the aspect-ratio to make the... |
Can PyCharm list all of Python errors in a project? | 14,902,181 | 44 | 2013-02-15T19:44:51Z | 14,902,200 | 51 | 2013-02-15T19:46:32Z | [
"python",
"python-2.7",
"compiler-errors",
"pycharm"
] | I use python 2.7 in a virtual environment and PyCharm 2.7 (new build as of feb 07 2013).
Whenever I open a python file in it that has unambiguous errors (equivalent to compile errors in other languages, e.g. using undeclared variables, calling non-existing functions), it shows red stripes in the gutter of the file.
S... | You can call [Code|Inspect Code](http://www.jetbrains.com/pycharm/webhelp/running-inspections.html) (formerly Analyze|Inspect Code, thanks to @CrackerJack9) to get all errors and warnings and ways to fix them.
In result panel you can choose to see only errors (red/yellow button at the left side). |
Can PyCharm list all of Python errors in a project? | 14,902,181 | 44 | 2013-02-15T19:44:51Z | 14,902,247 | 11 | 2013-02-15T19:49:10Z | [
"python",
"python-2.7",
"compiler-errors",
"pycharm"
] | I use python 2.7 in a virtual environment and PyCharm 2.7 (new build as of feb 07 2013).
Whenever I open a python file in it that has unambiguous errors (equivalent to compile errors in other languages, e.g. using undeclared variables, calling non-existing functions), it shows red stripes in the gutter of the file.
S... | Yes, run Analyze|Inspect Code and specify Whole project as the scope of analysis. |
json.loads allows duplicate keys in a dictionary, overwriting the first value | 14,902,299 | 10 | 2013-02-15T19:52:40Z | 14,902,564 | 17 | 2013-02-15T20:10:18Z | [
"python",
"json"
] | ```
>>> raw_post_data = request.raw_post_data
>>> print raw_post_data
{"group":{"groupId":"2", "groupName":"GroupName"}, "members":{"1":{"firstName":"fName","lastName":"LName","address":"address"},"1": {"firstName":"f_Name","lastName":"L_Name","address":"_address"}}}
>>> create_request = json.loads(raw_post_data)
>>> p... | [The rfc 4627 for `application/json` media type](http://tools.ietf.org/html/rfc4627#section-2.2) recommends unique keys but it doesn't forbid them explicitly:
> The names within an object SHOULD be unique.
From [rfc 2119](http://tools.ietf.org/html/rfc2119):
> **SHOULD** This word, or the adjective "RECOMMENDED", me... |
What is PasteDeploy and do I need to learn it if Eggs in Python are considered gone? | 14,902,732 | 5 | 2013-02-15T20:22:20Z | 14,905,095 | 9 | 2013-02-15T23:31:16Z | [
"python",
"pyramid",
"egg",
"python-3.3"
] | I'm quite new to Python. I've downloaded the Pyramid Framework and have been trying to understand it. It uses many separate tools for its work. For example some `PasteDeploy`. I tried to read [`PasteDeploy`'s manual](http://pythonpaste.org/deploy/) but can't understand anything. There is almost no valuable examples and... | The egg format is absolutely not deprecated and anywhere that you read that is lying to you. There are a lot of issues with Python packaging, but Pyramid embraces the state of the art.
Your link discusses goals for the future, but you can't deprecate something that does not yet have a replacement. It will be many year... |
How to create a dict with letters as keys in a concise way? | 14,902,904 | 8 | 2013-02-15T20:34:17Z | 14,902,939 | 15 | 2013-02-15T20:37:08Z | [
"python",
"dictionary"
] | I created an dictionary of the 26 alphabet letters like this:
```
aDict={
"a": 1,
"b": 2,
"c": 3,
"d": 4,
etc...
}
```
I'm trying make my code better and my question is,
is there any shorter way to do this without typing all these numbers out? | You can use [`string.ascii_lowercase`](https://docs.python.org/2/library/string.html#string.ascii_lowercase) and dict comprehension here.
```
In [4]: from string import ascii_lowercase as al
```
For Python 2.7+:
```
In [5]: dic = {x:i for i, x in enumerate(al, 1)}
```
For Python 2.6 or earlier:
```
In [7]: dic = d... |
Converting SVG with Embedded CSS to PDF in Python | 14,903,233 | 11 | 2013-02-15T20:58:39Z | 17,912,664 | 8 | 2013-07-28T20:41:03Z | [
"python",
"svg",
"pdf-generation"
] | I'm trying to generate a PDF image from an SVG image using Python. I've tried both [CairoSVG](http://cairosvg.org) and [svglib](http://pypi.python.org/pypi/svglib/). The problem is that in both cases the generated PDFs do not have any of the embedded CSS styles applied.
Here is a simple SVG file which should render a ... | (With help from @MonkeyWrench, since he didn't post an answer.)
According to the [documentation](http://cairosvg.org/user_documentation/),
> CairoSVG can use lxml to parse the SVG file, and tinycss plus cssselect to apply CSS not included in the style attribute of the tags. If these packages are not available, CSS wi... |
How can I do a batch insert into an Oracle database using Python? | 14,904,033 | 8 | 2013-02-15T21:58:37Z | 14,905,823 | 11 | 2013-02-16T01:07:29Z | [
"python",
"oracle",
"python-2.7",
"cx-oracle",
"batch-insert"
] | I have some monthly weather data that I want to insert into an Oracle database table but I want to insert the corresponding records in a batch in order to be more efficient. Can anyone advise as to how I'd go about doing this in Python?
For example let's say my table has four fields: a station ID, a date, and two valu... | Here's what I've come up with which appears to work well (but please comment if there's a way to improve this):
```
# build rows for each date and add to a list of rows we'll use to insert as a batch
rows = []
numberOfYears = endYear - startYear + 1
for i in range(numberOfYears):
for j in range(12):
# ma... |
In Fabric, how can I check if a Debian or Ubuntu package exists and install it if it does not? | 14,904,560 | 2 | 2013-02-15T22:38:13Z | 14,904,561 | 9 | 2013-02-15T22:38:13Z | [
"python",
"ubuntu",
"debian",
"fabric"
] | I required this to quickly install memcached as part of a Fabric script setting up test servers. Figured I'd record it here for future reference. | Pieced this together from this [superuser comment](http://superuser.com/questions/427318/#comment490784_427339) and this [stackoverflow answer](http://stackoverflow.com/a/10439058/1093087). (Note: I'm running as `root` rather than using `sudo`):
```
def package_installed(pkg_name):
"""ref: http:superuser.com/quest... |
NameError: global name 'long' is not defined | 14,904,814 | 6 | 2013-02-15T23:01:21Z | 14,904,834 | 16 | 2013-02-15T23:02:53Z | [
"python",
"long-integer",
"nameerror"
] | I have a Python version 3.3.0 and I am not sure why it does not let me do long for b and m here...
I tried to look up the answers on here and but nothing helped...thanks
im getting an error saying
```
NameError: global name 'long' is not defined
power = long(b) % long(m)
``` | In Python 3.x, [use `int` instead of `long`](http://docs.python.org/3.3/whatsnew/3.0.html#integers). |
Is there's any python library to output dictionary in beautiful ascii table? | 14,906,144 | 3 | 2013-02-16T02:00:51Z | 14,906,346 | 8 | 2013-02-16T02:37:27Z | [
"python",
"ascii"
] | I have quite huge dictionary in here, which just repeats all over again, and I'm searching for any code to display that dictionary in some ascii table, which would be outputed to command line. At least to have some generated columns for non-dimentional dictionary, and the rest could go as a key:value in cells, somethin... | you can use [`prettytable`](http://code.google.com/p/prettytable/wiki/Tutorial).
```
t = PrettyTable(['key', 'value'])
for key, val in dictionary.items():
t.add_row([key, val])
print t
```
You can also play with [`textwrap`](http://docs.python.org/2/library/textwrap.html) module to split the value on multiple line... |
matplotlib: aspect ratio in subplots with various y-axes | 14,907,062 | 5 | 2013-02-16T04:47:01Z | 14,911,939 | 7 | 2013-02-16T15:34:07Z | [
"python",
"matplotlib"
] | I would like the following code to produce 4 subplots of the same size with a common aspect ratio between the size of x-axis and y-axis set by me. Referring to the below example, I would like all of the subplots look exactly like the first one (upper left). What is wrong right now is that the size of the y-axis is corr... | I can't quite tell what you want from your question.
Do you want all of the plots to have the same data limits?
If so, use shared axes (I'm using `subplots` here, but you can avoid it if you want to stick to matlab-style code):
```
import matplotlib.pyplot as plt
import numpy as np
fig, axes = plt.subplots(nrows=2,... |
Python Tornado â how can I fix 'URLhandler takes exactly X arguments' error? | 14,907,489 | 4 | 2013-02-16T06:02:06Z | 14,908,972 | 8 | 2013-02-16T09:48:47Z | [
"python",
"tornado"
] | Here is the error:
```
TypeError: __init__() takes exactly 1 argument (3 given)
ERROR:root:Exception in callback <tornado.stack_context._StackContextWrapper object at 0x1017d4470>
Traceback (most recent call last):
File "/Library/Python/2.7/site-packages/tornado-2.4.1-py2.7.egg/tornado/ioloop.py", line 421, in _run... | @Princess of the Universe is right, but maybe this needs a bit of elaboration.
Tornado is going to call `__init__` on `RequestHandler` subclasses with the parameters `application, request, **kwargs`, so you need to allow for that.
You can do this:
```
def __init__(self, application, request, **kwargs):
self.titl... |
How to remove frame from matplotlib (pyplot.figure vs matplotlib.figure ) (frameon=False Problematic in matplotlib) | 14,908,576 | 29 | 2013-02-16T08:49:38Z | 14,913,405 | 51 | 2013-02-16T18:03:21Z | [
"python",
"matplotlib"
] | To remove frame in figure, I write
```
frameon=False
```
works perfect with `pyplot.figure`, but with `matplotlib.Figure` it only removes the gray background, the frame stays . Also, I only want the lines to show, and all the rest of figure be transparent.
with pyplot I can do what I want, I want to do it with matpl... | First off, if you're using `savefig`, be aware that it will override the figure's background color when saving unless you specify otherwise (e.g. `fig.savefig('blah.png', transparent=True)`).
However, to remove the axes' and figure's background on-screen, you'll need to set both `ax.patch` and `fig.patch` to be invisi... |
How to remove frame from matplotlib (pyplot.figure vs matplotlib.figure ) (frameon=False Problematic in matplotlib) | 14,908,576 | 29 | 2013-02-16T08:49:38Z | 28,720,127 | 33 | 2015-02-25T13:22:29Z | [
"python",
"matplotlib"
] | To remove frame in figure, I write
```
frameon=False
```
works perfect with `pyplot.figure`, but with `matplotlib.Figure` it only removes the gray background, the frame stays . Also, I only want the lines to show, and all the rest of figure be transparent.
with pyplot I can do what I want, I want to do it with matpl... | `ax.axis('off')`, will as Joe Kington pointed out, remove everything except the plotted line.
For those wanting to only remove the frame (border), and keep labels, tickers etc, one can do that by accessing the `spines` object on the axis. Given an axis object `ax`, the following should remove borders on all four sides... |
how can I use data posted from ajax in flask? | 14,908,864 | 31 | 2013-02-16T09:32:47Z | 17,082,422 | 28 | 2013-06-13T08:20:59Z | [
"jquery",
"python",
"ajax",
"flask"
] | I'm having trouble getting data POSTed from jquery ajax.
```
$('#clickme').click( function() {
var data = save_input(); // data
data['_sid'] = $survey_id; // survey_id injected from flask
data['_uip'] = $user_ip; // user_ip injected from flask, request.remote_addr
$.ajax({
type : "POST",
... | Try
```
$.ajax({
type : "POST",
url : "{{ url_for('mod.load_ajax') }}",
data: JSON.stringify(data, null, '\t'),
contentType: 'application/json;charset=UTF-8',
success: function(result) {
console.log(result);
}
});
```
Then from the server, you can refer to the variables in data like t... |
Difference between "global" and "import __main__" | 14,909,285 | 6 | 2013-02-16T10:29:35Z | 14,909,332 | 8 | 2013-02-16T10:35:11Z | [
"python"
] | I defined three functions that should change a global variable `x`.
```
def changeXto1():
global x
x = 1
def changeXto2():
from __main__ import x
x = 2
def changeXto3():
import __main__
__main__.x = 3
x = 0
print x
changeXto1()
print x
changeXto2()
print x
changeXto3()
print x
```
It gives ... | > Why doesn't `from __main__ import` work in `changeXto2`, while `import __main__` is working in `changeXto3`?
It works fine, it just doesn't do what you want. It copies the name and value into the local namespace instead of having the code access `__main__`'s namespace.
> Why do we need a global statement in Python ... |
Difference between "global" and "import __main__" | 14,909,285 | 6 | 2013-02-16T10:29:35Z | 14,909,627 | 7 | 2013-02-16T11:11:36Z | [
"python"
] | I defined three functions that should change a global variable `x`.
```
def changeXto1():
global x
x = 1
def changeXto2():
from __main__ import x
x = 2
def changeXto3():
import __main__
__main__.x = 3
x = 0
print x
changeXto1()
print x
changeXto2()
print x
changeXto3()
print x
```
It gives ... | This is related to how Python translate your code to bytecode (the compilation step).
When compiling a function, Python treat all variable that are assigned as local variable and perform an optimisation to reduce the number of name lookup it would have to do. Each local variable get assigned an index, and when the fun... |
How to specify where a Tkinter window opens? | 14,910,858 | 20 | 2013-02-16T13:30:49Z | 14,910,894 | 14 | 2013-02-16T13:35:25Z | [
"python",
"python-2.7",
"tkinter"
] | How can I tell a Tkinter window where to open, based on screen dimensions? I would like it to open in the middle. | Try this
```
import tkinter as tk
def center_window(width=300, height=200):
# get screen width and height
screen_width = root.winfo_screenwidth()
screen_height = root.winfo_screenheight()
# calculate position x and y coordinates
x = (screen_width/2) - (width/2)
y = (screen_height/2) - (heigh... |
How to specify where a Tkinter window opens? | 14,910,858 | 20 | 2013-02-16T13:30:49Z | 14,912,644 | 24 | 2013-02-16T16:47:26Z | [
"python",
"python-2.7",
"tkinter"
] | How can I tell a Tkinter window where to open, based on screen dimensions? I would like it to open in the middle. | This answer is based on [Rachel's answer](http://stackoverflow.com/a/14910894/839601). Her code did not work originally, but with some tweaking I was able to fix the mistakes.
```
import tkinter as tk
root = tk.Tk() # create a Tk root window
w = 800 # width for the Tk root
h = 650 # height for the Tk root
# get sc... |
Parsing \ in command line argument - python 2.7.3 | 14,912,771 | 5 | 2013-02-16T16:58:27Z | 14,912,784 | 8 | 2013-02-16T16:59:40Z | [
"python",
"bash",
"parsing",
"command-line-arguments"
] | I am calling a python script, `parse_input.py` from bash
`parse_input.py` takes a command line argument that has many `'\n'` characters in it.
Example input:
`$ python parse_input.py "1\n2\n"`
```
import sys
import pdb
if __name__ == "__main__":
assert(len(sys.argv) == 2)
data = sys.argv[1]
pdb.set_... | Bash doesn't interpret `\n` the way python does, it sees that as two characters.
You *can* interpret a literal `\n` (so two characters) as a newline in python by 'decoding' from `string_escape`:
```
data = data.decode('string_escape')
```
Demonstration:
```
>>> literal_backslash_n = '\\n'
>>> len(literal_backslash_... |
Parsing \ in command line argument - python 2.7.3 | 14,912,771 | 5 | 2013-02-16T16:58:27Z | 14,912,803 | 7 | 2013-02-16T17:02:04Z | [
"python",
"bash",
"parsing",
"command-line-arguments"
] | I am calling a python script, `parse_input.py` from bash
`parse_input.py` takes a command line argument that has many `'\n'` characters in it.
Example input:
`$ python parse_input.py "1\n2\n"`
```
import sys
import pdb
if __name__ == "__main__":
assert(len(sys.argv) == 2)
data = sys.argv[1]
pdb.set_... | Bash doesn't interpret escape characters in regular single and double-quoted strings. To get it to interpret (some) escape characters, you can use `$'...'`:
```
Words of the form $'string' are treated specially. The word expands to
string, with backslash-escaped characters replaced as specified by the
ANSI ... |
How to install win32com module in a virtualenv? | 14,913,607 | 9 | 2013-02-16T18:24:25Z | 24,545,697 | 17 | 2014-07-03T05:36:45Z | [
"python",
"virtualenv",
"pywin32"
] | I have installed both `virtualenv` and `pywin32` on my Windows 7 64-bit laptop, and each of them seems to work, but not with each other.
More specifically, if a virtualenv is active, then running `import win32com.client` in a python interactive shell fails with `No module named win32com.client`. The same expression su... | ### UPDATE 2016
There is now a version of pywin32 on PyPI that can be installed with pip. It is called `pypiwin32`, and it installs the package using the binary `wheel` format.
<https://pypi.python.org/pypi/pypiwin32>
```
pip install pypiwin32
```
That will work in a virtualenv, or with tox, etc.
---
Below this l... |
Python: how to distinguish between socket error and timeout? | 14,913,880 | 6 | 2013-02-16T18:54:23Z | 14,913,897 | 14 | 2013-02-16T18:56:17Z | [
"python",
"sockets",
"exception"
] | I'm having the following code:
```
try:
while 1:
s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.settimeout(5);
s.connect((HOST,PORT))
print("before send")
#time.sleep(10);
#s.sendall('GET / HTTP/1.1\r\nConnection: Keep-Alive\r\nHost: www.google.lt\r\n\r\n')
... | `socket.timeout` is a subclass of `socket.error`. Really it's `socket.timeout`. When you catch a `socket.error` first, you catch a more general case.
```
>>> issubclass(socket.timeout, socket.error)
True
```
This code is correct:
```
except socket.timeout:
print("timeout error")
except socket.error:
print("socket ... |
How to apply max & min boundaries to a value without using conditional statements | 14,914,254 | 4 | 2013-02-16T19:30:25Z | 14,914,573 | 8 | 2013-02-16T20:02:48Z | [
"python"
] | **Problem:**
Write a Python function, clip(lo, x, hi) that returns lo if x is less than lo; hi if x is greater than hi; and x otherwise. For this problem, you can assume that lo < hi.
Don't use any conditional statements for this problem. Instead, use the built in Python functions min and max. You may wish to read th... | Here is a solution, assuming that lo < hi.
```
def clip(lo, x, hi):
return max(lo, min(hi, x))
```
How it works in each case:
* **lo, when x < lo**: *if lo < hi*, then x < hi, so `min(hi, x)` returns `x` and `max(lo, x)` returns `lo`.
* **hi, when x > hi**: `min(hi, x)` returns `hi` and *if lo < hi*, `max(lo, hi... |
In Python, find out number of differences between two ordered lists | 14,914,615 | 6 | 2013-02-16T20:08:31Z | 14,914,635 | 13 | 2013-02-16T20:10:31Z | [
"python",
"list"
] | I want to compare two lists of same length
```
a = [1, 3, 5, 7, 9]
b = [1, 2, 5, 7, 3]
```
and find out the number of differences `n`, in this case it'll be `n = 2`, and also return an error if the length are not equal. What's the pythonic way of doing this? | The simplest way to do this is to use [the `sum()` built-in](http://docs.python.org/3/library/functions.html#sum) and a [generator expression](http://www.youtube.com/watch?v=pShL9DCSIUw):
```
def differences(a, b):
if len(a) != len(b):
raise ValueError("Lists of different length.")
return sum(i != j fo... |
In class object, how to auto update attributes? | 14,916,284 | 6 | 2013-02-16T23:26:54Z | 14,916,491 | 10 | 2013-02-16T23:53:18Z | [
"python",
"class",
"attributes"
] | I have a class which has multiple attributes that are related, for example:
```
class SomeClassï¼
def __init__(self, n=0):
self.list = range(n)
self.listsquare = [ x**2 for x in self.a ]
```
If I make an object normally that would no problem, with
```
a = SomeClass(10)
```
I will get 2 lists, `... | if updating one property due to an update on another property is what you're looking for (instead of recomputing the value of the downstream property on access) use property setters:
```
class SomeClass(object):
def __init__(self, n):
self.list = range(0, n)
@property
def list(self):
retur... |
Reshaping dataframes in pandas based on column labels | 14,916,358 | 9 | 2013-02-16T23:37:04Z | 14,917,572 | 11 | 2013-02-17T03:05:57Z | [
"python",
"numpy",
"pandas",
"scipy",
"multi-index"
] | What is the best way to reshape the following dataframe in pandas? This DataFrame `df` has `x,y` values for each sample (`s1` and `s2` in this case) and looks like this:
```
In [23]: df = pandas.DataFrame({"s1_x": scipy.randn(10), "s1_y": scipy.randn(10), "s2_x": scipy.randn(10), "s2_y": scipy.randn(10)})
In [24]: df
... | I'm assuming you already have the DataFrame. In which case you can just turn the columns into a MultiIndex and use stack then reset\_index. Note that you'll then have to rename and reorder the columns and sort by sample to get *exactly* what you posted in the question:
```
In [4]: df = pandas.DataFrame({"s1_x": scipy.... |
How do I stack vectors of different lengths in NumPy? | 14,916,407 | 7 | 2013-02-16T23:42:41Z | 14,916,455 | 15 | 2013-02-16T23:48:15Z | [
"python",
"numpy"
] | How do I stack column-wise `n` vectors of shape `(x,)` where x could be any number?
For example,
```
from numpy import *
a = ones((3,))
b = ones((2,))
c = vstack((a,b)) # <-- gives an error
c = vstack((a[:,newaxis],b[:,newaxis])) #<-- also gives an error
```
`hstack` works fine but concatenates along the wrong dime... | Short answer: you can't. NumPy does not support jagged arrays natively.
Long answer:
```
>>> a = ones((3,))
>>> b = ones((2,))
>>> c = array([a, b])
>>> c
array([[ 1. 1. 1.], [ 1. 1.]], dtype=object)
```
gives an array that *may or may not* behave as you expect. E.g. it doesn't support basic methods like `sum` or... |
Multiply Adjacent Elements | 14,916,957 | 3 | 2013-02-17T01:01:08Z | 14,917,025 | 10 | 2013-02-17T01:13:14Z | [
"python",
"tuples",
"multiplication"
] | I have a tuple of integers such as `(1, 2, 3, 4, 5)` and I want to produce the tuple `(1*2, 2*3, 3*4, 4*5)` by multiplying adjacent elements. Is it possible to do this with a one-liner? | Short and sweet. Remember that `zip` only runs as long as the shortest input.
```
print tuple(x*y for x,y in zip(t,t[1:]))
``` |
sum of nested list in Python | 14,917,092 | 4 | 2013-02-17T01:25:01Z | 14,917,111 | 15 | 2013-02-17T01:29:07Z | [
"python",
"list"
] | I try to sum a list of nested elements
e.g, numbers=[1,3,5,6,[7,8]], sum=30
I wrote the following code
```
def nested_sum(L):
sum=0
for i in range(len(L)):
if (len(L[i])>1):
sum=sum+nested_sum(L[i])
else:
sum=sum+L[i]
return sum
```
The above code gives following error... | You need to use `isinstance` to check whether an element is a list or not. Also, you might want to iterate over the actual list, to make things simpler.
```
def nested_sum(L):
total = 0 # don't use `sum` as a variable name
for i in L:
if isinstance(i, list): # checks if `i` is a list
tota... |
python - lxml: enforcing a specific order for attributes | 14,917,943 | 4 | 2013-02-17T04:20:23Z | 17,654,556 | 7 | 2013-07-15T12:43:42Z | [
"python",
"xml",
"lxml"
] | I have an XML writing script that outputs XML for a specific 3rd party tool.
I've used the original XML as a template to make sure that I'm building all the correct elements, but the final XML does not appear like the original.
I write the attributes in the same order, but lxml is writing them in its own order.
I'm ... | It looks like lxml serializes attributes in the order you set them:
```
>>> from lxml import etree as ET
>>> x = ET.Element("x")
>>> x.attrib['a'] = '1'
>>> x.attrib['b'] = '2'
>>> ET.tostring(x)
'<x a="1" b="2"/>'
>>> y = ET.Element('y')
>>> y.attrib['b'] = '2'
>>> y.attrib['a'] = '1'
>>> ET.tostring(y)
'<y b="2" a="... |
python - lxml: enforcing a specific order for attributes | 14,917,943 | 4 | 2013-02-17T04:20:23Z | 22,596,064 | 9 | 2014-03-23T19:38:37Z | [
"python",
"xml",
"lxml"
] | I have an XML writing script that outputs XML for a specific 3rd party tool.
I've used the original XML as a template to make sure that I'm building all the correct elements, but the final XML does not appear like the original.
I write the attributes in the same order, but lxml is writing them in its own order.
I'm ... | # OrderedDict of attributes
As of lxml 3.3.3 (perhaps also in earlier versions) you can pass an [OrderedDict](http://docs.python.org/2/library/collections.html#collections.OrderedDict) of attributes to the `lxml.etree.(Sub)Element` constructor and the order will be preserved when using `lxml.etree.tostring(root)`:
``... |
Generating postgresql user password | 14,918,763 | 10 | 2013-02-17T07:01:35Z | 14,941,263 | 14 | 2013-02-18T16:50:28Z | [
"python",
"postgresql"
] | I tried to generate password for `postgres` using `hashlib` from Python.
```
>>> import hashlib
>>> hashlib.md5("psql123").hexdigest()
2636d1ddc54901f98d011ffe050c0eb7
```
But postgresql requires `md5` prefix, so then
```
sudo -u postgres psql
ALTER USER postgres PASSWORD 'md52636d1ddc54901f98d011ffe050c0eb7';
```
... | Postgres' password hash is very close to what you did, it just needs the username to be included as follows:
```
pghash = "md5" + hashlib.md5(password + username).hexdigest()
```
AFAIK, the postgres docs don't really document this hash format at all, and seem to assume admins will rarely deal with these hashes direc... |
How to create sqlalchemy to json | 14,920,080 | 4 | 2013-02-17T10:22:26Z | 14,929,005 | 15 | 2013-02-18T03:24:17Z | [
"python",
"json",
"sqlalchemy"
] | I have a sqlalchemy result
```
labels = session.query(
LabelsData,
LabelsData.id,
LabelsData.name,
LabelsData.color
).filter(LabelsData.deleted==False).all()
```
And I want convert this result to JSON, but how I can do it? | It looks like your `LabelsData` object is a SQLAlchemy model. You need to serialize it before dumping it to JSON. Here's a short example that extracts all the columns from your `LabelsData` object and converts the results of your query to JSON:
```
from json import dumps
from sqlalchemy.orm import class_mapper
def se... |
Time difference in seconds from numpy.timedelta64 | 14,920,903 | 29 | 2013-02-17T12:07:10Z | 14,920,923 | 23 | 2013-02-17T12:09:25Z | [
"python",
"datetime",
"numpy"
] | How to get time difference in seconds from numpy.timedelta64 variable?
```
time1 = '2012-10-05 04:45:18'
time2 = '2012-10-05 04:44:13'
dt = np.datetime64(time1) - np.datetime64(time2)
print dt
0:01:05
```
I'd like to convert `dt` to number (int or float) representing time difference in seconds. | You can access it through the "wrapped" datetime item:
```
>>> dt.item().total_seconds()
65.0
```
*Explanation*: here `dt` is an [array scalar](http://docs.scipy.org/doc/numpy/reference/arrays.scalars.html) in `numpy`, which is a zero rank array or 0-dimensional array. So you will find the `dt` here also has all the ... |
Time difference in seconds from numpy.timedelta64 | 14,920,903 | 29 | 2013-02-17T12:07:10Z | 14,921,192 | 43 | 2013-02-17T12:39:20Z | [
"python",
"datetime",
"numpy"
] | How to get time difference in seconds from numpy.timedelta64 variable?
```
time1 = '2012-10-05 04:45:18'
time2 = '2012-10-05 04:44:13'
dt = np.datetime64(time1) - np.datetime64(time2)
print dt
0:01:05
```
I'd like to convert `dt` to number (int or float) representing time difference in seconds. | To get number of seconds from `numpy.timedelta64()` object using [`numpy` 1.7 experimental datetime API](http://docs.scipy.org/doc/numpy-dev/reference/arrays.datetime.html#datetime-and-timedelta-arithmetic):
```
seconds = dt / np.timedelta64(1, 's')
``` |
python Image PIL to binary Hex | 14,921,055 | 2 | 2013-02-17T12:24:21Z | 14,921,165 | 9 | 2013-02-17T12:34:13Z | [
"python",
"image",
"hex",
"python-imaging-library",
"binaryfiles"
] | ```
from PIL import Image
from PIL import ImageDraw
from PIL import ImageFont
import urllib.request
import io
import binascii
data = urllib.request.urlopen('http://pastebin.ca/raw/2311595').read()
r_data = binascii.unhexlify(data)
stream = io.BytesIO(r_data)
img = Image.open(stream)
draw = ImageDraw.Draw(img)
font = I... | The `img` object needs to be saved again; write it to another `BytesIO` object:
```
output = io.BytesIO()
img.save(output, format='JPEG')
```
then get the written data with the [`.getvalue()` method](http://docs.python.org/3/library/io.html#io.BytesIO.getvalue):
```
hex_data = output.getvalue()
```
The PIL-for-pyth... |
Python - Finding word frequencies of list of words in text file | 14,921,436 | 8 | 2013-02-17T13:11:48Z | 14,921,469 | 9 | 2013-02-17T13:15:07Z | [
"python",
"text",
"frequency"
] | I am trying to speed up my project to count word frequencies. I have 360+ text files, and I need to get the total number of words and the number of times each word from another list of words appears. I know how to do this with a single text file.
```
>>> import nltk
>>> import os
>>> os.chdir("C:\Users\Cameron\Desktop... | [collections.Counter()](http://docs.python.org/2/library/collections.html#collections.Counter) has this covered if I understand your problem.
The example from the docs would seem to match your problem.
```
# Tally occurrences of words in a list
cnt = Counter()
for word in ['red', 'blue', 'red', 'green', 'blue', 'blue... |
How can I return a default value for an attribute? | 14,923,465 | 20 | 2013-02-17T16:48:25Z | 14,923,478 | 10 | 2013-02-17T16:49:44Z | [
"python",
"attributes",
"default",
"void"
] | I have an object "`myobject`", which might return `None`. If it returns `None`, it won't return an attribute "`id`":
```
a = myobject.id
```
So when myobject is `None`, the stament above results in a AttributeError:
```
AttributeError: 'NoneType' object has no attribute 'id'
```
If `myobject` is None, then I want "... | The simplest way is to use the ternary operator:
```
a = myobject.id if myobject is not None else None
```
The ternary operator returns the first expression if the middle value is true, otherwise it returns the latter expression.
Note that you could also do this in another way, using exceptions:
```
try:
a = my... |
How can I return a default value for an attribute? | 14,923,465 | 20 | 2013-02-17T16:48:25Z | 14,923,509 | 48 | 2013-02-17T16:52:59Z | [
"python",
"attributes",
"default",
"void"
] | I have an object "`myobject`", which might return `None`. If it returns `None`, it won't return an attribute "`id`":
```
a = myobject.id
```
So when myobject is `None`, the stament above results in a AttributeError:
```
AttributeError: 'NoneType' object has no attribute 'id'
```
If `myobject` is None, then I want "... | You should use the [`getattr`](http://docs.python.org/2/library/functions.html#getattr) wrapper instead of directly retrieving the value of `id`.
```
a = getattr(myobject, 'id', None)
```
This is like saying "I would like to retrieve the attribute `id` from the object `myobject`, but if there is no attribute `id` ins... |
Loading huge XML files and dealing with MemoryError | 14,924,200 | 6 | 2013-02-17T17:58:47Z | 14,924,389 | 8 | 2013-02-17T18:18:13Z | [
"python",
"xml",
"beautifulsoup",
"mediawiki"
] | I have a very large XML file (20GB to be exact, and yes, I need all of it). When I attempt to load the file, I receive this error:
```
Python(23358) malloc: *** mmap(size=140736680968192) failed (error code=12)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug
Traceback (most recent ... | Do *not* use BeautifulSoup to try and such a large parse XML file. Use the [ElementTree API](http://docs.python.org/2/library/xml.etree.elementtree.html) instead. Specifically, use the [`iterparse()` function](http://docs.python.org/2/library/xml.etree.elementtree.html#xml.etree.ElementTree.iterparse) to parse your fil... |
how to choose a random line from a text file | 14,924,721 | 6 | 2013-02-17T18:48:46Z | 14,924,739 | 12 | 2013-02-17T18:50:38Z | [
"python",
"file",
"random",
"python-3.3"
] | I am trying to make a lottery program for my school (we have an economic system).
My program generates numbers and saves it off into a text file. When I want to "pull" numbers out of my generator I want it to ensure that there is a winner.
Q: How do I have Python select a random line out of my text file and give my o... | > How do I have python select a random line out of my text file and give my output as that number?
Assuming the file is relatively small, the following is perhaps the easiest way to do it:
```
import random
line = random.choice(open('data.txt').readlines())
``` |
Default filter in Django model | 14,925,090 | 3 | 2013-02-17T19:24:35Z | 14,925,152 | 11 | 2013-02-17T19:30:34Z | [
"python",
"django",
"model"
] | Is is possible to set a default filter in Django models?
Something like:
```
class MyModel(models.Model):
timestamp = models.DateTimeField(default=datetime.utcnow)
active = models.BooleanField(default=True)
class Meta:
ordering = ['-timestamp']
filtering = [active=True]
``` | You'll have to override the [manager](https://docs.djangoproject.com/en/dev/topics/db/managers/):
```
class MyModelManager(models.Manager):
def get_queryset(self):
return super(MyModelManager, self).get_queryset().filter(active=True)
class MyModel(models.Model):
timestamp = models.DateTimeField(defaul... |
Upsert and Multi flag in pymongo | 14,925,134 | 6 | 2013-02-17T19:28:50Z | 14,928,445 | 18 | 2013-02-18T02:04:08Z | [
"python",
"mongodb",
"pymongo"
] | I am working on pymongo and this is my document:
```
{
"_id": ObjectId("51211b57f07ddaa377000000"),
"assignments": {
"0": {
"0": {
"_id": ObjectId("5120dd7400a4453d58a0d0ec")
},
"1": {
"_id": ObjectId("5120dd8e00a4453d58a0d0ed")
},
"2": {
"_id": ... | The problem is that the two flags you are passing in aren't `upsert` and `multi`. Based on the documentation of PyMongo's `Collection.update` (found [here](http://api.mongodb.org/python/current/api/pymongo/collection.html#pymongo.collection.Collection.update)), it looks like you might be passing in values for the `upse... |
Gevent-Websocket Detecting closed connection | 14,925,413 | 6 | 2013-02-17T19:57:20Z | 15,286,867 | 7 | 2013-03-08T04:43:31Z | [
"python",
"websocket",
"bottle",
"gevent"
] | I'm using gevent-websocket with bottle.py to serve log-files.
How can I detect that the websocket connection is closed from the client-side?
At the moment I'm just writing until I get a broken pipe error:
```
return sock.send(data, flags)
error: [Errno 32] Broken pipe
```
But I would like to properly detect on the s... | Try testing for `if ws.socket is not None:` before sending data out on the socket. |
Add remember headers to json response using json renderer | 14,925,652 | 4 | 2013-02-17T20:21:56Z | 14,926,243 | 10 | 2013-02-17T21:25:40Z | [
"python",
"json",
"authentication",
"pyramid"
] | this is the current way I use to add remeber headers to response:
```
@view_config(route_name='login', renderer='json', request_method='POST')
def post_login(request):
...
... authentication logic
...
headers = remeber(request, login)
return HTTPFound(location=came_from, headers=headers)
```
but my js ... | You can set that information on the response directly, as documented in the [Vary Attributes of Rendered Responses section](http://docs.pylonsproject.org/projects/pyramid/en/latest/narr/renderers.html#varying-attributes-of-rendered-responses) of the Pyramid manual:
```
@view_config(route_name='login', renderer='json',... |
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