Python Newbie

Roy Smith roy at panix.com
Sun Feb 24 17:22:36 CET 2013


In article <mailman.2410.1361721167.2939.python-list at python.org>,
 Chris Angelico <rosuav at gmail.com> wrote:

> The "dunder" methods ("d"ouble "under"score, leading and trailing),
> also called "magic methods", are the implementations of various
> special features. For instance, indexing foo[1] is implemented using
> the __getitem__ method. Here's a list:
> 
> http://docs.python.org/3.3/reference/datamodel.html#special-method-names
> 
> You'll seldom, if ever, call these methods directly.

On the other hand, once you get into building your own classes, you will 
often be *writing* them.  The most common are __str__(), __repr__(), and 
__unicode__(), and of course, __init__().

A quick look over my current project shows 471 classes, and I've defined:

      1 __del__
      1 __getattr__
      1 __iter__
      1 __new__
      2 __cmp__
      2 __len__
      3 __ne__
      4 __contains__
      9 __eq__
     14 __str__
     38 __unicode__
     62 __repr__
    140 __init__

Not to mention the boilerplate:

if __name__ == '__main__":

which shows up all over the place.



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