catching exceptions in expressions

Vaclav Dvorak dvorakv at
Thu Aug 7 01:20:53 CEST 2003

Hello, Sheilas and Bruces!

I found myself writing something like this lately:

try: a = int(s)
except ValueError: a = 99
try: b = int(t)
except ValueError: b = 99
try: c = int(u)
except ValueError: c = 99

Not enough to make me want to create a function, but enough to be 
annoying. :-) I was thinking about something like this:

a = int(s) except ValueError then 99


a = int(s) or 99 if ValueError

or even a different approach:

         a, b, c = int(s), int(t), int(u)
except ValueError:
         retry with 99

or yet another:

a, b, c = 99, 99, 99
         a = int(s)
         b = int(t)
         c = int(u)
except ValueError:
         continue [execution on next line - my comment]

I like the first one the most. Imagine:

lambda x:
      (A/x except NameError then 1/x) except ZeroDivisionError then 99

Catching exceptions in lambdas - how do you like that? :-)
Comments? Should I write a PEP? Am I missing something obvious? Has this 
been debated a million times over already?


Vaclav Dvorak  <dvorakv at>

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