Mercurial > hg > config

annotate python/example/mutable_defaults.py @ 717:d6f659169b49

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
mutable defaults -> example
author Jeff Hammel <k0scist@gmail.com>
date Thu, 23 Oct 2014 15:29:48 -0700
parents python/mutable_defaults.py@434c65593612
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
91
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
1 #!/usr/bin/env python
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
2
184
434c65593612 link to documentation
Jeff Hammel <jhammel@mozilla.com>
parents: 91
diff changeset
3 # see also: http://www.daniweb.com/software-development/python/threads/66697
434c65593612 link to documentation
Jeff Hammel <jhammel@mozilla.com>
parents: 91
diff changeset
4
91
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
5 class Foo(object):
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
6 def __init__(self, mutable=['default']):
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
7 self.foo = mutable
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
8 self.foo.append(1)
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
9
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
10 if __name__ == '__main__':
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
11 bar = Foo()
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
12 print len(bar.foo)
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
13 fleem = Foo()
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
14 print len(fleem.foo)
70544c7406e2 add illustration program for mutable arguments, since this comes up a bunch
Jeff Hammel <jhammel@mozilla.com>
parents:
diff changeset
15 assert len(fleem.foo) == 2, "Don't use default mutable arguments!"