Mike Kent wrote:
> Roman wrote:
> > Thanks for your help
> >
> > My intention is to create matrix based on parsed csv file. So, I would
> > like to have a list of columns (which are also lists).
> >
> > I have made the following changes and it still doesn't work.
> >
> >
> > cnt = 0
> > p=[[], [], [], [], [], [], [], [], [], [], []]
> > reader = csv.reader(file("f:\webserver\inp.txt"), dialect="excel",
> > quotechar="'", delimiter='\t')
> > for line in reader:
> > if cnt > 6:
> > break
> > j = 0
> > for col in line:
> > p[j].append(col)
> > j=j+1
> > cnt = cnt + 1
> >
> > print p
>
> p[j] does not give you a reference to an element inside p. It gives
> you a new sublist containing one element from p. You then append a
> column to that sublist. Then, since you do nothing more with that
> sublist, YOU THROW IT AWAY.
>
> Try doing:
>
> p[j] = p[j].append(col)
>
No, this doesn't work. append is an in-place operation, and you'll end
up setting p[j] to it's return, which is None.
Iain
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