64 lines
1.7 KiB
Plaintext
64 lines
1.7 KiB
Plaintext
From: donn at u.washington.edu (Donn Cave)
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Date: 23 Apr 1999 00:18:03 GMT
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Subject: Emulating C++ coding style
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References: <371F8FB7.92CE674F@pk.highway.ne.jp> <371F9D0C.4F1205BB@pop.vet.uu.nl>
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Message-ID: <7foe7r$15mi$1@nntp6.u.washington.edu>
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Content-Length: 1458
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X-UID: 48
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Martijn Faassen <faassen at pop.vet.uu.nl> writes:
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...
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|> 4. access to class's members using "::"
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|> e.g. some_class::static_value
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|> e.g. some_class::static_func(x)
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| Python does not support static methods (or 'class methods'). Usually a
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| module level global function suffices for this purpose.
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| A static value can be created like this (besides using a global variable
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| in a module):
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| class Foo:
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| self.shared = 1
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| def __init__(self):
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| print self.shared
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Just a nit-pick on this particular item - I tried that already, a
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couple of days ago, so I know it won't work! You meant to say,
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class Foo:
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shared = 1
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Now a couple of further observations. Per the question, yes, that
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variable ("attribute") is accessible in the class scope:
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print Foo.shared
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As well as in the instance scope, as shown in Martijn's example.
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However, it may come as a surprise that if you assign to that attribute
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in the instance scope, for example through "self" in a method, what
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you get is a new reference bound in the instance scope, and other
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instances still see the original class value.
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...
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def privatize(self):
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self.shared = 0
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f1 = Foo()
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f2 = Foo()
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f1.privatize()
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print Foo.shared, f1.shared, f2.shared
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1 0 1
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It's not much like C++ here, but it's uncanny how it reeks of Python!
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Namespaces, references!
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Donn Cave, University Computing Services, University of Washington
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donn at u.washington.edu
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