On 13/10/2010 18:17, Chris Rebert wrote:
On Wed, Oct 13, 2010 at 9:56 AM, Seebs<usenet-nos...@seebs.net> wrote:
On 2010-10-12, MRAB<pyt...@mrabarnett.plus.com> wrote:
<snip>
Line 51
The __init__ method should always return None. There's no need to be
explicit about it, just use a plain "return".
The real issue here is that I was assuming that open('nonexistent') returned
None rather than raising an exception.
For future reference, the significant majority of things in Python
raise exceptions upon encountering errors rather than returning error
values of some sort.
Aside from APIs which explicitly provide a parameter to be returned as
a default value in case of error (e.g. getattr(obj, name, default)),
the only common exception* I can come up with off the top of my head
is str.find()**, and even that has an exception-throwing cousin,
str.index().
Cheers,
Chris
--
*No pun intended; I just didn't want to have to break out a thesaurus.
**Returns -1 rather than raising ValueError
The re.search and so forth return Match objects or None.
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