[Tutor] writing csv files

[Peter Otten]

prasad rao wrote:

> hello!
> 
> I got a problem writing csv file.
> 
> 1)
>   csvw=csv.writer(open('/home/prasad/kkm','w'),
> dialect='excel',fieldnames=names)
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> TypeError: 'fieldnames' is an invalid keyword argument for this function
> 
> 2)
>  for x in csvr:
> ...    y=lambda x: ''.join([x.split()[3],x.split()[-3],x.split()[-6]])
> ...    csvw.write(y)
> ...
> Traceback (most recent call last):
>   File "<stdin>", line 3, in <module>
> AttributeError: '_csv.writer' object has no attribute 'write'
> 
> At  http://www.python.org/dev/peps/pep-0305/  they are using  the function
> write
>  and the argument fieldnames.
> 
> Where is the problem?Please someone show me  a way to do it.

The PEP is not uptodate. If you are using Python 2.6 have a look at

http://docs.python.org/library/csv.html

You can find the documentation for other versions of Python via 
http://docs.python.org/index.html

If you are using 2.6 the following might work:

# prepare rows
rows = (row.split() for row in csvr)
rows = ((row[3], row[-3], row[-6]) for row in rows)

with open(filename, "wb") as out:
    w = csv.writer(out, dialect="excel")
    w.writerow(names) # write header
    w.writerows(rows) # write data

Peter