reducing if statements and error handling
doug.fort at verizon.net
Tue Aug 21 15:35:42 CEST 2001
> Another easy newbie question here... Suppose I have a method that
> accepts a string (called 'value') as an argument. I want the method
> to check to see if the contents of the string is all numbers. Here's
> my logic:
> def checkvalue(value):
> if value.isdigit():
> print 'success: ' + value + ' is a valid entry'
> return 1
> print 'error: ' + value + ' is NOT a valid entry'
> return -1
> 1) can I reduce this "if" logic down to one statement, perhaps using
> 2) is there a recommended approach for throwing errors? In this case,
> I'd want to throw an error if the text is not a number and stop
> processing. Can I define a custom exception to do that? Should I
> catch the error in the logic that called the method and throw the
> exception there if the method returns a "-1", or should I throw the
> exception here?
Instead of the whole checkvalue function, why not say
number = int(value)
except ValueError, instance:
With regards to number 2), I find that when I use exceptions judiciously I
don't need to have functions return a 'success' value. You can define
custom exceptions easily. It's a good idea to derive them from Exception,
but not absolutely neccessary.
Doug Fort <dougfort at dougfort.net>
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