REPOST: Re: cmp [__eq__]

[Daniel Yoo]

Mark McEahern <markjunk at mceahern.com> wrote:
:> Perhaps then could someone explain to me how one compares classes
:> useing the == operator, or indeed if this bad programming practice.

: By overloading the __cmp__ method.  Don't confuse the return value of
: __cmp__ with whether or not the result of the comparison is that the two
: instances being compared are equal.  Examine this sample and note that
: __cmp__ isn't merely used to determine equality.  It is also used to
: determine sort order.

And if you just want to be able to compare two things for equality,
it's probably better to write an __eq__ method instead.


Unlike __cmp__, __eq__ is meant to be a boolean function, so it should
be more familiar to use.  There's more information on __eq__ and the
other rich comparison methods here:

    http://www.python.org/doc/current/ref/customization.html

Good luck!

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From: Daniel Yoo <dyoo at hkn.eecs.berkeley.edu>
Newsgroups: comp.lang.python
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