diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index e3a3fd60f6003c..30c898aa704844 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -972,15 +972,6 @@ and :term:`generators ` which incur interpreter overhead. iterators = cycle(islice(iterators, num_active)) yield from map(next, iterators) - def partition(predicate, iterable): - """Partition entries into false entries and true entries. - - If *predicate* is slow, consider wrapping it with functools.lru_cache(). - """ - # partition(is_odd, range(10)) → 0 2 4 6 8 and 1 3 5 7 9 - t1, t2 = tee(iterable) - return filterfalse(predicate, t1), filter(predicate, t2) - def subslices(seq): "Return all contiguous non-empty subslices of a sequence." # subslices('ABCD') → A AB ABC ABCD B BC BCD C CD D @@ -1603,26 +1594,6 @@ The following recipes have a more mathematical flavor: >>> ''.join(chain(*input_iterators)) 'dijkopqr' - >>> def is_odd(x): - ... return x % 2 == 1 - - >>> evens, odds = partition(is_odd, range(10)) - >>> list(evens) - [0, 2, 4, 6, 8] - >>> list(odds) - [1, 3, 5, 7, 9] - >>> # Verify that the input is consumed lazily - >>> input_iterator = iter(range(10)) - >>> evens, odds = partition(is_odd, input_iterator) - >>> next(odds) - 1 - >>> next(odds) - 3 - >>> next(evens) - 0 - >>> list(input_iterator) - [4, 5, 6, 7, 8, 9] - >>> list(subslices('ABCD')) ['A', 'AB', 'ABC', 'ABCD', 'B', 'BC', 'BCD', 'C', 'CD', 'D'] @@ -1767,6 +1738,17 @@ The following recipes have a more mathematical flavor: return true_iterator(), chain(transition, it) + def partition(predicate, iterable): + """Partition entries into false entries and true entries. + + If *predicate* is slow, consider wrapping it with functools.lru_cache(). + """ + # partition(is_odd, range(10)) → 0 2 4 6 8 and 1 3 5 7 9 + t1, t2 = tee(iterable) + return filterfalse(predicate, t1), filter(predicate, t2) + + + .. doctest:: :hide: @@ -1802,3 +1784,23 @@ The following recipes have a more mathematical flavor: 'ABC' >>> ''.join(remainder) 'dEfGhI' + + >>> def is_odd(x): + ... return x % 2 == 1 + + >>> evens, odds = partition(is_odd, range(10)) + >>> list(evens) + [0, 2, 4, 6, 8] + >>> list(odds) + [1, 3, 5, 7, 9] + >>> # Verify that the input is consumed lazily + >>> input_iterator = iter(range(10)) + >>> evens, odds = partition(is_odd, input_iterator) + >>> next(odds) + 1 + >>> next(odds) + 3 + >>> next(evens) + 0 + >>> list(input_iterator) + [4, 5, 6, 7, 8, 9]