Basic question

[Alex Martelli]

Gabriel Genellina <gagsl-py2 at yahoo.com.ar> wrote:

> En Sat, 12 May 2007 20:13:48 -0300, Alex Martelli <aleax at mac.com> escribió:
> 
> > Cesar G. Miguel <cesar.gomes at gmail.com> wrote:
> >> -------------------
> >> L = []
> >> file = ['5,1378,1,9', '2,1,4,5']
> >> str=''
> >> for item in file:
> >>       L.append([float(n) for n in item.split(',')])
> >
> > The assignment to str is useless (in fact potentially damaging because
> > you're hiding a built-in name).
> >
> > L = [float(n) for item in file for n in item.split(',')]
> >
> > is what I'd call Pythonic, personally (yes, the two for clauses need to
> > be in this order, that of their nesting).
> 
> But that's not the same as requested - you get a plain list, and the
> original was a list of lists:
> 
> L = [[float(n) for n in item.split(',')] for item in file]

Are we talking about the same code?!  What I saw at the root of this
subthread was, and I quote:

> L = []
> file = ['5,1378,1,9', '2,1,4,5']
> str=''
> for item in file:
>    j=0
>    while(j<len(item)):
>       while(item[j] != ','):
>          str+=item[j]
>          j=j+1
>        if(j>= len(item)): break
> 
>       if(str != ''):
>        L.append(float(str))
>          str = ''
> 
>       j=j+1
> 
> print L

This makes L a list of floats, DEFINITELY NOT a list of lists.

> And thanks for my "new English word of the day": supererogatory :)

You're welcome!  Perhaps it's because I'm not a native speaker of
English, but I definitely do like to widen my vocabulary (and others').


Alex