Rick van Hattem
30 lines
684 B
Python
30 lines
684 B
Python
# Write a groupby function that returns lists of results instead of
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# generators.
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import pprint
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def groupby(iterable, key=None):
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'''
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Return a dictionary of lists of items grouped by the key function.
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Note that as opposed to the itertools.groupby function, this function
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does not require the iterable to be sorted.
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'''
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if key is None:
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key = lambda x: x
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groups = {}
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for item in iterable:
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groups.setdefault(key(item), []).append(item)
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return groups
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def main():
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# Demo data from the itertools docs
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pprint.pprint(groupby('AAAABBBCCDAABBB'))
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pprint.pprint(groupby('AAAABBBCCD'))
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if __name__ == '__main__':
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main()
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