Thanks to Kevin and Andrew for your suggestions. I do know the exact
number of columns and rows of the files, but I forgot to mention that
the files contain headers for each column. I realized that this is
important, since I tried the abovementioned solutions and they both seem
to require only-numeric data. How can I tell python to ignore the
headers and import only the numeric data in the columns? Thanks so much
for your help. Best Regards, Peter




--- In PhillyPug@yahoogroups.com, Kevin Hill <khill@...> wrote:
>
> Peter Perez wrote:
> >
> >
> > Hi all,
> >
> > I need to read a tab-delimited file with numeric data in columns,
and
> > then create an array with each of the columns of the file. Although
I
> > am a newbie in Python, I thought it would be as easy (or easier)
than
> > in Matlab, but that doesn't seem to be the case. I haven't found any
> > way to do that, neither in the tutorials nor the online
documentation.
> > So far, I only know how to do this:
> >
> > filename = 'ptrace.csv'
> > reader = csv.reader(open(filename,'r'),dialect='excel-tab')
>
> You should use the "rb" flag - csv likes the file opened as binary.
>
> >
> > But I don't know how to load the numeric data into an array that
Python
> > can manipulate. Could somebody help me please? Thank you very much
for
> > your kind attention. Best regards, Peter
>
> Do you know how many columns you have in the file? And if so, does the
> column count vary for each row?
>
> Something like this would work:
>
> col1 = []
> col2 = []
> col3 = []
>
> def populateColumns(r):
> col1.append(r[0])
> col2.append(r[1])
> col3.append(r[2])
>
> reader = csv.reader(open(filename,'rb'),dialect='excel-tab')
> for row in reader:
> populateColumns(row)
>
> Just define as many lists as you need - one list per column.
>
> - khill
>