Posted Monday, May 7th, 2007 at 12:22 pm under python, tech.

iteranything

Here’s a Python function to iterate over pretty much anything. In the extremely unlikely event that anyone uses this code, note that if you pass keyword arguments the order of the resulting iteration is not defined (as with iterating through any Python dictionary).

from itertools import chain
import types

def iteranything(*args, **kwargs):
    for arg in chain(args, kwargs.itervalues()):
        t = type(arg)
        if t == types.StringType:
            yield arg
        elif t == types.FunctionType:
            for i in arg():
                yield i
        else:
            try:
                i = iter(arg)
            except TypeError:
                yield arg
            else:
                while True:
                    try:
                        yield i.next()
                    except StopIteration:
                        break

if __name__ == ‘__main__’:
    def gen1():
        yield 1
        yield 2

    def gen2():
        yield 3
        yield 4

    assert list(iteranything()) == []
    assert list(iteranything([])) == []
    assert list(iteranything([[]])) == [[]]
    assert list(iteranything([], [])) == []
    assert list(iteranything(3)) == [3]
    assert list(iteranything(3, 4)) == [3, 4]
    assert list(iteranything(3, 4, dog=‘fido’)) == [3, 4, ‘fido’]
    assert list(iteranything(3, 4, func=gen1)) == [3, 4, 1, 2]
    assert list(iteranything(3, 4, func=gen1())) == [3, 4, 1, 2]
    assert list(iteranything(3, 4, func=iteranything)) == [3, 4]
    assert list(iteranything(3, 4, func=iteranything())) == [3, 4]
    assert list(iteranything(3, 4, func=iteranything(‘a’, ‘b’, c=‘z’))) ==
        [3, 4, ‘a’, ‘b’, ‘z’]
    assert list(iteranything(3, 4, func=iteranything(‘a’,
        iteranything(5, 6), c=‘z’))) == [3, 4, ‘a’, 5, 6, ‘z’]
    assert list(iteranything(None, ‘xxx’, True)) == [None, ‘xxx’, True]
    assert list(iteranything(3, 4, [5, 6])) == [3, 4, 5, 6]
    assert list(iteranything(3, 4, gen1, gen2)) == [3, 4, 1, 2, 3, 4]
    assert list(iteranything(3, 4, gen1(), gen2())) == [3, 4, 1, 2, 3, 4]
    assert list(iteranything(1, 2, iteranything(3, 4), None)) ==
        [1, 2, 3, 4, None]
    assert list(iteranything(1, 2, iteranything(3, iteranything(1, 2,
        iteranything(3, 4), None)))) == [1, 2, 3, 1, 2, 3, 4, None]

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