[Tutor] Re: one line code

[Wolfram Kraus]

Christian Meesters wrote:
> 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.)

Well, not really in one line, but one function & one line:
def f(x):
     try:
         return float(x)
     except ValueError:
         return x

l2 = [f(x) for x in l]

(I could imagine some obfuscated one-line LC using sting.digits an "or", 
but that will look too much like Perl ;-))

> 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
> 
HTH,
Wolfram