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annotate python/mutable_defaults.py @ 91:70544c7406e2

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add illustration program for mutable arguments, since this comes up a bunch
author Jeff Hammel <jhammel@mozilla.com>
date Tue, 21 Sep 2010 08:30:19 -0700
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children 434c65593612
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91
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
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1 #!/usr/bin/env python
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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2
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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3 class Foo(object):
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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4 def __init__(self, mutable=['default']):
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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5 self.foo = mutable
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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6 self.foo.append(1)
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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7
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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8 if __name__ == '__main__':
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9 bar = Foo()
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10 print len(bar.foo)
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11 fleem = Foo()
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12 print len(fleem.foo)
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
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13 assert len(fleem.foo) == 2, "Don't use default mutable arguments!"