Re: List mapping question

[Steven Bethard]

Marc Huffnagle wrote:
I have a number of variables that I want to modify (a bunch of strings 
that I need to convert into ints).  Is there an easy way to do that 
other than saying:

 > a = int(a)
 > b = int(b)
 > c = int(c)
I tried
 > [i = int(i) for i in [a, b, c]]
but that didn't work because it was creating a list with the values of 
a, b and c instead of the actual variables themselves, then trying to 
set a string equal to an integer, which it really didn't like.
Actually, that didn't work because it's a SyntaxError to have an 
assigment statement inside a list comprehension:

py> [i = int(i) for i in [a, b, c]]
Traceback (  File "<interactive input>", line 1
    [i = int(i) for i in [a, b, c]]
       ^
SyntaxError: invalid syntax
You could try something like:
py> a, b, c
('1', '2', '3')
py> a, b, c = [int(i) for i in (a, b, c)]
py> a, b, c
(1, 2, 3)
For a few variables, this is probably a reasonable solution.  For more 
than 4 or 5 though, it's going to get unreadable.  Of course for that 
many variables, you should probably be keeping them in a list instead of 
as separate names anyway...

Steve
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