[Chicago] Ode to <>
ianb at colorstudy.com
Fri Sep 1 17:39:23 CEST 2006
Brian Ray wrote:
> On Sep 1, 2006, at 10:19 AM, Martin Maney wrote:
>> __eq__(self, other)
> Oh yes, ok, I. Well, Python has me covered.
> But still, I do not see a way to define <>. IMHO, there also should
> be a way.
__neq__ (not equal). If you don't define __neq__ it will use "not
__eq__". Of course, there's no way to make != and <> act differently.
Note you can also do funny tricks with this stuff, since these methods
don't have to return True/False. This is how SQLObject/SQLBuilder
expressions work (and you can see the same technique elsewhere). For
def __init__(self, expr):
self.expr = expr
def __eq__(self, other):
return Expr('%s=%s' % (self, other))
def __neq__(self, other):
return Expr('%s<>%s' % (self, other))
def __gt__(self, other):
return Expr('%s>%s' % (self, other))
def __getattr__(self, attr):
return Expr('%s.%s' % (self, attr))
# and so on...
person = Expr('person')
print person.fname == 'Joe'
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org
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