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python Programming Glossary: usingWhat is a metaclass in Python? http://stackoverflow.com/questions/100003/what-is-a-metaclass-in-python any object. First you can create a class in a function using class def choose_class name ... if name 'foo' ... class Foo.. does when you use the keyword class and it does so by using a metaclass. What are metaclasses finally Metaclasses are the.. said a class object stay with me here with the name Foo by using what is in __metaclass__ . If Python can't find __metaclass__..
Fastest way to list all primes below N in python http://stackoverflow.com/questions/2068372/fastest-way-to-list-all-primes-below-n-in-python primesfrom3to 18.4 ambi_sieve 29.3 Timings were measured using the command python mtimeit s import primes primes. method 10000000.. N # http zerovolt.com p 88 ''' Returns a list of primes N using wheel criterion 2 3 5 30 Copyright 2009 by zerovolt.com This.. end return a list of all the prime numbers end using the Sieve of Atkin. # Code by Steve Krenzel Sgk284@gmail.com..
Python “is” operator behaves unexpectedly with integers http://stackoverflow.com/questions/306313/python-is-operator-behaves-unexpectedly-with-integers 257 True # yet the literal numbers compare properly I am using Python 2.5.2. Trying some different versions of Python it appears..
How do you split a list into evenly sized chunks in Python? http://stackoverflow.com/questions/312443/how-do-you-split-a-list-into-evenly-sized-chunks-in-python had a good solution to this for lists of any length e.g. using generators. This should work l range 1 1000 print chunks l 10..
Is there any way to kill a Thread in Python? http://stackoverflow.com/questions/323972/is-there-any-way-to-kill-a-thread-in-python want it to exit and wait for the thread to exit properly using join . The thread should check the stop flag at regular intervals...
Flattening a shallow list in Python http://stackoverflow.com/questions/406121/flattening-a-shallow-list-in-python But neither of these methods are as efficient as using itertools.chain from itertools import chain list chain mi.image_set.all.. it's probably better style to avoid operator magic by using chain.from_iterable like so chain itertools.chain.from_iterable.. Django's iterable QuerySet s which it appears that you're using in the question. Edit This is probably as good as a reduce anyway..
Python: How do I pass a variable by reference? http://stackoverflow.com/questions/986006/python-how-do-i-pass-a-variable-by-reference can't even mutate the object. Okay this is a little confusing. Let's have some examples. List a mutable type Let's try to.. my_string If you really wanted to avoid using a return value you could create a class to hold your value and..
Using numpy to build an array of all combinations of two arrays http://stackoverflow.com/questions/1208118/using-numpy-to-build-an-array-of-all-combinations-of-two-arrays numpy to build an array of all combinations of two arrays I'm..
Should you always favor xrange() over range()? http://stackoverflow.com/questions/135041/should-you-always-favor-xrange-over-range 3 range is a generator anyway and xrange does not exist. Using range may make your Python 2.x code more portable going forward...
Get last n lines of a file with Python, similar to tail http://stackoverflow.com/questions/136168/get-last-n-lines-of-a-file-with-python-similar-to-tail trying to finesse alignment with physical OS blocks. Using these high level I O packages I doubt you'll see any performance..
Differences between isinstance() and type() in python http://stackoverflow.com/questions/1549801/differences-between-isinstance-and-type-in-python code fragments Which way is considered to be more pythonic Using type import types if type a is types.DictType do_something if.. if type b in types.StringTypes do_something_else Using isinstance if isinstance a dict do_something if isinstance b..
Python dictionary, keep keys/values in same order as declared http://stackoverflow.com/questions/1867861/python-dictionary-keep-keys-values-in-same-order-as-declared keep the explicit order that I declared the keys values in Using Python 2.6 python dictionary order share improve this question..
Fastest way to list all primes below N in python http://stackoverflow.com/questions/2068372/fastest-way-to-list-all-primes-below-n-in-python # Using Numpy def ambi_sieve n # http tommih.blogspot.com 2009 04 fast..
Flatten (an irregular) list of lists in Python http://stackoverflow.com/questions/2158395/flatten-an-irregular-list-of-lists-in-python Any problems python list share improve this question Using generator functions can make your example a little easier to..
How to get current CPU and RAM usage in Python? http://stackoverflow.com/questions/276052/how-to-get-current-cpu-and-ram-usage-in-python be a few possible ways of extracting that from my search Using a library such as PSI that currently seems not actively developed.. activity since 2007 it seems and no support for Windows . Using platform specific code such as using a os.popen ps or similar..
What are “named tuples” in Python? http://stackoverflow.com/questions/2970608/what-are-named-tuples-in-python import sqrt line_length sqrt pt1 0 pt2 0 2 pt1 1 pt2 1 2 Using a named tuple it becomes more readable from collections import..
Using Django time/date widgets in custom form http://stackoverflow.com/questions/38601/using-django-time-date-widgets-in-custom-form Django time date widgets in custom form How can I use the nifty..
Using global variables in a function other than the one that created them http://stackoverflow.com/questions/423379/using-global-variables-in-a-function-other-than-the-one-that-created-them global variables in a function other than the one that created..
Python code to pick out all possible combinations from a list? http://stackoverflow.com/questions/464864/python-code-to-pick-out-all-possible-combinations-from-a-list the appropriate numbers. Does anyone know of a better way Using map maybe python combinations share improve this question..
What's the difference between list and tuples in Python? http://stackoverflow.com/questions/626759/whats-the-difference-between-list-and-tuples-in-python sequences. Tuples have structure lists have order. Using this distinction makes code more explicit and understandable...
Python's use of __new__ and __init__? http://stackoverflow.com/questions/674304/pythons-use-of-new-and-init done with a Factory and that's the best way to do it. Using __new__ is not a good clean solution so please consider the..
Using MultipartPostHandler to POST form-data with Python http://stackoverflow.com/questions/680305/using-multipartposthandler-to-post-form-data-with-python MultipartPostHandler to POST form data with Python Problem..
http://stackoverflow.com/questions/886221/does-django-scale have got to stop somewhere Dec 2009 UPDATE Blog post about Using Django to build high traffic site michaelmoore.com described..
Simple Digit Recognition OCR in OpenCV-Python http://stackoverflow.com/questions/9413216/simple-digit-recognition-ocr-in-opencv-python 16 features are explained in the paper Letter Recognition Using Holland Style Adaptive Classifiers . Although i didn't understand..
Why is the same SQLite query being 30 times slower when fetching only twice as many results? http://stackoverflow.com/questions/10531898/why-is-the-same-sqlite-query-being-30-times-slower-when-fetching-only-twice-as-m TABLE feature ~100000 rows ' 0 1 1 u'SEARCH TABLE spectrum USING INDEX fk_spectrum_scahn_start_time_1 scan_start_time AND scan_start_time.. ~3125 rows ' 0 2 0 u'SEARCH TABLE MSMS_precursor USING INDEX fk_MSMS_precursor_spectrum_spectrum_id_1 spectrum_spectrum_id.. TABLE feature ~100000 rows ' 0 1 1 u'SEARCH TABLE spectrum USING INDEX fk_spectrum_scahn_start_time_1 scan_start_time AND scan_start_time..
How to use USING clause in Alembic/SQLAchemy? http://stackoverflow.com/questions/20663497/how-to-use-using-clause-in-alembic-sqlachemy to use USING clause in Alembic SQLAchemy I would like to change column type.. existing_nullable True I got an error HINT Please use USING clause for carrying out the conversion The SQL statement generated..
Optimizing performance of Postgresql database writes in Django? http://stackoverflow.com/questions/9423539/optimizing-performance-of-postgresql-database-writes-in-django rows matched by id UPDATE tbl SET col_a tmp_x.col_a USING tmp_x WHERE tbl.id tmp_x.id Finally drop the temporary table..
How can I speed up update/replace operations in PostgreSQL? http://stackoverflow.com/questions/962361/how-can-i-speed-up-update-replace-operations-in-postgresql '00 00 00 00 00 02' 'v3' 'v4' 'v5' ... DELETE FROM item USING temp_item WHERE item.key temp_item.key INSERT INTO item key..
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