Skip to main content

Makes permuations; Based on ActiveState recipe 190465

Project description


This package is made from the xpermutations recipe submitted to ActiveState by Ulrich Hoffman.

The documentation provided therein follows and is assumed to be under the Creative Commons Attribution 3.0 license.

Install with pip or easy_install:

sudo pip install xpermutations

Recipe Documentation (Ulrich Hoffman)

Permutations and combinations are often required in algorithms that do a complete search of the solution space. They are typically rather large so it’s best not to compute them entirely but better to lazily generate them. This recipe uses Python 2.2 generators to create appropriate generator objects, that can be use for example as ranges in for loops.

This recipe provides both combinations and permutations and lazily generates them. You can do arbitrary calculations on the permutation/combination items not just print them.

If you require the complete list of permutations, just use the built-in list() operator. Note that the resulting list can be huge.

All x-generators defined here yield sequences with elements from the original sequence. Their difference is in which elements they take:

xpermutations() takes all elements from the sequence, order matters.

xcombinations() takes n distinct elements from the sequence, order matters.

xuniqueCombinations() takes n distinct elements from the sequence, order is irrelevant.

xselections() takes n elements (not necessarily distinct) from the sequence, order matters.

Note that ‘distinct’ means “different elements in the orginal sequence” and not “different value”, i.e.:

>>> list(xuniqueCombinations('aabb', 2))
[['a', 'a'], ['a', 'b'], ['a', 'b'], ['a', 'b'], ['a', 'b'], ['b', 'b']]

Compare the latter to:

>>> all_different = list(set('aabb'))
>>> list(xuniqueCombinations(all_different, 2))
[['a', 'b']]

If your sequence has only items with unique values, you won’t notice the difference (no pun intended).


Set theoreticians may take issue with the nomenclature.

Home Page & Repository

Home Page:




>>> " ".join("".join(x) for x in xcombinations("1234", 2))
'12 13 14 21 23 24 31 32 34 41 42 43'


>>> " ".join("".join(x) for x in xuniqueCombinations("1234", 2))
'12 13 14 23 24 34'


>>> " ".join("".join(x) for x in xselections("1234", 2))
'11 12 13 14 21 22 23 24 31 32 33 34 41 42 43 44'


>>> " ".join("".join(x) for x in xpermutations("123"))
'123 132 213 231 312 321'

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

xpermutations-1.0.1.tar.gz (4.8 kB view hashes)

Uploaded source

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Huawei Huawei PSF Sponsor Microsoft Microsoft PSF Sponsor NVIDIA NVIDIA PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page