The Itertools_python of Python permutations and combinations

Python 2.6 introduces the Itertools module, making the implementation of the permutation combination simple:

Copy Code code as follows:

Import Itertools

Orderly arrangement: e.g., 4 number of selected 2 ranked:

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>>> Print List (itertools.permutations ([1,2,3,4],2))
[(1, 2), (1, 3), (1, 4), (2, 1), (2, 3), (2, 4), (3, 1), (3, 2), (3, 4), (4, 1), (4, 2), (4-3)]

Unordered combination: The number of e.g.,4 selected 2:

Copy Code code as follows:

>>> Print List (itertools.combinations ([1,2,3,4],2))
[(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]