[Python-ideas] Default return values to int and float

[MRAB]

On 05/10/2011 18:56, Ethan Furman wrote:
> Nick Coghlan wrote:
>> On Oct 5, 2011 10:32 AM, "Ethan Furman" wrote:
>>> Ron Adam wrote:
>>>> On Wed, 2011-10-05 at 19:08 +1300, Greg Ewing wrote:
>>>>> Guido van Rossum wrote:
>>>>>
>>>>>> I'm out of ideas here. But of all these, str.find is probably still
>>>>>> the worst -- I've flagged bugs caused by it too many times to count.
>>>>>
>>>>> Could a with-statement be used here somehow?
>>>>>
>>>>>     with finding(x, s) as i:
>>>>>         ...
>>>>
>>>>
>>>> Or an iterator.
>>>>
>>>>     for i in finding(x, s):
>>>>          ...
>>>
>>>
>>> How would the case of not found be handled in either of these 
>>> proposals?
>>
>> By never executing the body of the loop. It's still a thoroughly 
>> unnatural API for the 0 or 1 case, though.
>
>
> Let me rephrase:
>
>   found = "I don't want to get into the cart!".find('z')
>   if found >= 0:
>       # do stuff if found
>   else:
>       # do stuff if not found
>
> or
>
>   found = "I don't want to get into the cart!".find('n')
>   while found >= 0:
>       # do stuff if found
>       found = "I don't want to get into the cart!".find('n', found+1)
>       if found == -1:
>           break
>   else:
>       print('false branch')
>       # do stuff if not found
>
> How would we reliably get the false branch with the above proposals?
>
We've had the discussion before about how to handle the case when the 
body of the
loop isn't executed at all.

I had the thought that a possible syntax could be:

   found = "I don't want to get into the cart!".find('n')
   while found >= 0:
       # do stuff if found
       found = "I don't want to get into the cart!".find('n', found+1)
   or:
       print('false branch')
       # do stuff if not found

but I think I'll leave it there.