"Roy Smith" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Bob Greschke <[EMAIL PROTECTED]> wrote:
>>I miss being able to do something like this in Python
>>
>>1f (I = a.find("3")) != -1:
>> print "It's here: ", I
>>else:
>> print "No 3's here"
>>
>>where I gets assigned the index returned by find() AND the if statement
>>gets
>>to do its job in the same line. Then you don't have to have another like
>>that specifically gets the index of the "3". Is there a way to do this in
>>Python?
>
> It is a deliberate and fundamental design decision in Python that
> assignment is a statement, not an expression with side effects. This
> means you often need an "extra" line compared to a classic C "assign
> and test" idiom such as you have above. I, like you, often miss the
> compactness of the C idiom, but there it is.
>
> It's also unpythonic to return magic values to indicate failure.
> Throwing an exception would be the more normal way of doing it. So,
> I'd expect the above to translate into something like:
>
> try:
> i = a.find("3")
> print "It's here: ", i
> except NotFound:
> print "No 3's here"
Nuts. I guess you're right. It wouldn't be proper. Things are added or
proposed every day for Python that I can't even pronounce, but a simple 'if
(I = a.find("3")) != -1' isn't allowed. Huh. It might be time to go back
to BASIC. :)
I think your way would work if .find() were replaced with .index(). I'm
just trying to clean up an if/elif tree a bit, so using try would make
things bigger.
Thanks!
Bob
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