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

[Masklinn]

On 2011-10-04, at 08:58 , David Townshend wrote:

>> 
>>   def try_convert(target_type, obj, default, ignored=(TypeError,))
>>       try:
>>           return target_type(obj)
>>       except ignored:
>>           return default
>> 
> 
> The problem with a general convert function is that to make it work, you
> would need to account for several variations and the signature gets rather
> clunky.  Personally, I think that the try format:
> 
>    try:
>        return float('some text')
>    except ValueError:
>        return 42
> 
> is more readable than
> 
>    try_convert('some text', float, 42, (ValueError,))
> 
> because it is clear what it does. The second form is shorter, but not as
> descriptive. However,
> 
>    float('some text', default=42)
> 
> follows the existing syntax quite nicely, and is more readable than either
> of the other options.
> 
> A generalised try_convert method would be useful, but I think I would rather
> see a one-line version of the try statements, perhaps something like this:
> 
>    x = try float('some text') else 42 if ValueError
That's basically what the function you've rejected does (you got the arguments order wrong):

    x = try_convert(float, 'some text', default=42, ignored=ValueError)

Just rename an argument or two and you have the exact same thing.