[Tutor] one line code

[Pierre Barbier de Reuille]

Mmmhhh ... not strictly one line but ...

import re

float_str = re.compile(r"^\s*[+-]?(\d+(\.\d*)?|\.\d+)([eE][+-]?\d+)?\s*$")

val = [ ( (float_str.match(s) and [float(s)]) or [s])[0] for s in l2 ]

It's not really "readable" but well ... it works ^_^

Pierre

Christian Meesters a écrit :
> Hi
> 
> Yesterday night I was thinking about the following problem:
> I do have a list like l = ['1','2','3','abc','','4'] - for instance like 
> a list one could get from a file import with the csv module (which is 
> where my 'problem' comes from). Now I would like to generate the 
> following list, preferably with one line of code:
> l2 = [1.0,2.0,3.0,'abc','',4.0]
> With other words I'd like to tell Python: Convert into a float if 
> possible, otherwise append anyway. Is this possible in one line? (Right 
> now my code is a lot longer.)
> I was trying with 'filter' + lambda forms, list comprehensions etc., but 
> could not find a solution. Could it be that a C-like solution with '?' 
> and ':' is more straightforward than a solution with Python or am I just 
> too blind to see a real pythonic solution here?
> 
> I am aware that putting a solution in one line of code might be against 
> the 'Zen of Python' (... Complex is better than complicated ... 
> Readability counts ...), but since I'm just asking out of curiosity, 
> perhaps I'll get an answer anyway. ;-)
> 
> Thanks a lot in advance.
> Cheers
> Christian
> 
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> 

-- 
Pierre Barbier de Reuille

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