Difference: __iadd__ and __add__

[Ronny Mandal]

Can someone please explain or point me to articles regarding these two
methods?

Thanks.

 

[tomerfiliba]

__add__ is called for the + operator
__iadd__ is called for the += operator
if __iadd__ doesnt exist, fallbacks to __add__

you know what they say for such things: rtfm.

 

[Jonathan Gardner]

I would like to point out that it isn't entirely obvious where to find
documentation for this particular thing. I know from experience where
to go, but I remember spending a long time trying to hunt this down.

For reference, you may want to check out the index of the language
reference manual.

http://www.python.org/doc/2.4.2/ref/genindex.html

 

[Peter Hansen]

I would like to point out that it isn't entirely obvious where to find
documentation for this particular thing. I know from experience where
to go, but I remember spending a long time trying to hunt this down.

I'd like to point out it should be obvious, at least as far as going to
http://docs.python.org and typing "__iadd__" into the Search field in
the upper right should be an obvious first step...

For reference, you may want to check out the index of the language
reference manual.

http://www.python.org/doc/2.4.2/ref/genindex.html

That one is the second hit in those results...

(It does seem to require reading a few of those pages to learn enough to
answer the original question. To be fair, I didn't find (in a few
minutes) any page that explicitly states what (e-mail address removed)
said, about += falling back to __add__ if __iadd__ is not defined,
though I didn't try searching for it directly.)

-Peter