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Diffstat (limited to 'Doc/library/itertools.rst')
| -rw-r--r-- | Doc/library/itertools.rst | 14 |
1 files changed, 5 insertions, 9 deletions
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index 0d20410..c9d4c60b 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -96,7 +96,7 @@ loops that truncate the stream. .. function:: combinations(iterable, r) - Return successive *r* length combinations of elements in the *iterable*. + Return *r* length subsequences of elements from the input *iterable*. Combinations are emitted in lexicographic sort order. So, if the input *iterable* is sorted, the combination tuples will be produced @@ -106,9 +106,6 @@ loops that truncate the stream. value. So if the input elements are unique, there will be no repeat values in each combination. - Each result tuple is ordered to match the input order. So, every - combination is a subsequence of the input *iterable*. - Equivalent to:: def combinations(iterable, r): @@ -375,11 +372,10 @@ loops that truncate the stream. Equivalent to nested for-loops in a generator expression. For example, ``product(A, B)`` returns the same as ``((x,y) for x in A for y in B)``. - The leftmost iterators correspond to the outermost for-loop, so the output - tuples cycle like an odometer (with the rightmost element changing on every - iteration). This results in a lexicographic ordering so that if the - inputs iterables are sorted, the product tuples are emitted - in sorted order. + The nested loops cycle like an odometer with the rightmost element advancing + on every iteration. This pattern creates a lexicographic ordering so that if + the input's iterables are sorted, the product tuples are emitted in sorted + order. To compute the product of an iterable with itself, specify the number of repetitions with the optional *repeat* keyword argument. For example, |