python Programming Glossary: itertools

How to generate all permutations of a list in Python

http://stackoverflow.com/questions/104420/how-to-generate-all-permutations-of-a-list-in-python

been released yet will have a builtin solution in the itertools module import itertools itertools.permutations 1 2 3 python.. have a builtin solution in the itertools module import itertools itertools.permutations 1 2 3 python algorithm permutation combinatorics.. builtin solution in the itertools module import itertools itertools.permutations 1 2 3 python algorithm permutation combinatorics..

Remove items from a list while iterating in Python

http://stackoverflow.com/questions/1207406/remove-items-from-a-list-while-iterating-in-python

for details . Also I liked Cides' suggestion that uses itertools . However there is no non iterator filterfalse so it will have.. is no non iterator filterfalse so it will have to be. from itertools import ifilterfalse somelist list ifilterfalse determine somelist..

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

a pure numpy implementation. It's ca. 5 faster than using itertools. import numpy as np def cartesian arrays out None Generate..

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

2 3 3 np.nonzero sieve 0 1 1 if __name__ '__main__' import itertools import sys def test f1 f2 num print 'Testing f1 and f2 return.. f1 f1.func_name f2 f2.func_name if not all a b for a b in itertools.izip_longest f1 num f2 num sys.exit Error s s s s f1.func_name..

The Python yield keyword explained

http://stackoverflow.com/questions/231767/the-python-yield-keyword-explained

access to a resource. Itertools your best friend The itertools module contains special functions to manipulate iterables. Ever.. Map Zip without creating another list Then just import itertools . An example Let's see the possible orders of arrival for a.. orders of arrival for a 4 horse race horses 1 2 3 4 races itertools.permutations horses print races itertools.permutations object..

Python - Is a dictionary slow to find frequency of each character?

http://stackoverflow.com/questions/2522152/python-is-a-dictionary-slow-to-find-frequency-of-each-character

to support unicode # usr bin env python import codecs itertools operator sys import numpy filename sys.argv 1 if len sys.argv..

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

11..20 .. 991..999 I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed..

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.. methods are as efficient as using itertools.chain from itertools import chain list chain mi.image_set.all for mi in h.get_image_menu.. operator magic by using chain.from_iterable like so chain itertools.chain.from_iterable 1 2 3 5 89 6 print list chain 1 2 3 5 89..

What is the most “pythonic” way to iterate over a list in chunks?

http://stackoverflow.com/questions/434287/what-is-the-most-pythonic-way-to-iterate-over-a-list-in-chunks

question Modified from the recipes section of Python's itertools docs def grouper iterable n fillvalue None args iter iterable..

Comprehension for flattening a sequence of sequences?

http://stackoverflow.com/questions/457215/comprehension-for-flattening-a-sequence-of-sequences

sequence of sequences maybe a list of tuples I can use itertools.chain to flatten it. But sometimes I feel like I would rather.. pair in a sequence. I use a string as a sequence here from itertools import chain seq '012345' swapped_pairs zip seq 1 2 seq 2 swapped_pairs..

Get the cartesian product of a series of lists in Python

http://stackoverflow.com/questions/533905/get-the-cartesian-product-of-a-series-of-lists-in-python

share improve this question In Python 2.6 import itertools for element in itertools.product somelists print element share.. question In Python 2.6 import itertools for element in itertools.product somelists print element share improve this answer..

Iterating over every two elements in a list

http://stackoverflow.com/questions/5389507/iterating-over-every-two-elements-in-a-list

You need a pairwise or grouped implementation from itertools import izip def pairwise iterable s s0 s1 s2 s3 s4 s5 ... a.. y in pairwise l print d d d x y x y Or more generally from itertools import izip def grouped iterable n s s0 s1 s2 ...sn 1 sn sn.. not be confused with the pairwise recipe in Python's own itertools documentation which yields s s0 s1 s1 s2 s2 s3 ... as pointed..

Rolling or sliding window iterator in Python

http://stackoverflow.com/questions/6822725/rolling-or-sliding-window-iterator-in-python

There's one in an old version of the Python docs with itertools examples from itertools import islice def window seq n 2 Returns.. version of the Python docs with itertools examples from itertools import islice def window seq n 2 Returns a sliding window of..

join list of lists in python

http://stackoverflow.com/questions/716477/join-list-of-lists-in-python

print el python share improve this question import itertools a a b c print list itertools.chain a share improve this answer..