On Tue, Oct 4, 2011 at 9:37 AM, Masklinn masklinn@masklinn.net wrote:
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.
Same functionality, but try_convert is a function with lots of arguments
whereas my alternative is an expression. But to be honest, I don't really like either. In cases that require the level of control that try_convert provides, the try statement is cleaner. The point I'm really trying to make is that my initial proposal was for a specific but common use case (float and int), not a general-purpose conversion tool.