[Tutor] get columns from txt file

[Prasad, Ramit]

> I have a group of files in a directory.
> I want to extract from  files whose names start with  bb_   column number 5 to
> an excel file. I have 6  bb_  files, therefore I want to get 6 columns (5th
> column from each file)
> This code is working,with the following errors:
> * I get the data in only one column, instead of six
> * I get white cell after every extracted cell
> 
> I've got  help from http://mail.python.org/pipermail/tutor/2004-
> November/033474.html, though it is not working for me
> 
> This is my code:
> 
> 
> import os
> import fnmatch
> import csv
> 
> path = '//......'
> files=os.listdir(path)
> csv_out=csv.writer(open('out.csv', 'w'), delimiter='  ')
> 
> for infile in files:
> 
>         if fnmatch.fnmatch(infile, 'bb_*'):
>                 print infile
> 
>                 filename= path+infile
>                 print filename
> 
>                 f=open(filename)
>                 for line in f.readlines():
>                        b=line.split('\t')
>                        csv_out.writerow(b[5])
>                f.close

You get 6 lines because csv_out.writerow writes a row and then
goes to the next line.

What you want to do is read through each file and append each
value to a list. Once you are done reading, write the list using
the csv module.

I am not sure what you mean by "white cell after every extracted
cell" but if you mean spaces you can use (where output is a list).

output.append(b[5].strip()) 

Also, csv files should be opened using 'wb' not 'w' otherwise
you will get extra lines in the file. Maybe this is what you
meant by white cell?


Ramit


Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology
712 Main Street | Houston, TX 77002
work phone: 713 - 216 - 5423

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