anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
Thanks in advance
17  60017 
On Aug 27, 12:16 pm, SimonPalmer <simon.pal...@g mail.comwrote:
anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
Thanks in advance
You have to iterate each row and count them -- there's no other way
without supporting information (since each row length is naturally
variable, you can't even use the file size as an indicator).
Something like:
row_count = sum(1 for row in csv.reader( open('filename. csv') ) )
hth
Jon.
On Aug 27, 12:29 pm, "Simon Brunning" <si...@brunning online.net>
wrote:
2008/8/27 SimonPalmer <simon.pal...@g mail.com>:
anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
len(list(csv.re ader(open('my.c sv'))))
--
Cheers,
Simon B.
si...@brunningo nline.nethttp://www.brunningonl ine.net/simon/blog/
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
2008/8/27 Jon Clements <jo****@googlem ail.com>:
>len(list(csv.r eader(open('my. csv'))))
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
I do try to avoid premature optimization. ;-)
--
Cheers,
Simon B.
On Aug 27, 12:41 pm, Jon Clements <jon...@googlem ail.comwrote:
On Aug 27, 12:29 pm, "Simon Brunning" <si...@brunning online.net>
wrote:
2008/8/27 SimonPalmer <simon.pal...@g mail.com>:
anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
len(list(csv.re ader(open('my.c sv'))))
--
Cheers,
Simon B.
si...@brunningo nline.nethttp://www.brunningonl ine.net/simon/blog/
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
Thanks to everyone for their suggestions.
In my case the number of rows is never going to be that large (<200)
so it is a practical if slightly inelegant solution
On Aug 27, 12:50 pm, SimonPalmer <simon.pal...@g mail.comwrote:
On Aug 27, 12:41 pm, Jon Clements <jon...@googlem ail.comwrote:
On Aug 27, 12:29 pm, "Simon Brunning" <si...@brunning online.net>
wrote:
2008/8/27 SimonPalmer <simon.pal...@g mail.com>:
anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
len(list(csv.re ader(open('my.c sv'))))
--
Cheers,
Simon B.
si...@brunningo nline.nethttp://www.brunningonl ine.net/simon/blog/
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
Thanks to everyone for their suggestions.
In my case the number of rows is never going to be that large (<200)
so it is a practical if slightly inelegant solution
actually not resolved...
after reading the file throughthe csv.reader for the length I cannot
iterate over the rows. How do I reset the row iterator?
On Aug 27, 12:48 pm, "Simon Brunning" <si...@brunning online.net>
wrote:
2008/8/27 Jon Clements <jon...@googlem ail.com>:
len(list(csv.re ader(open('my.c sv'))))
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
I do try to avoid premature optimization. ;-)
--
Cheers,
Simon B.
:)
On Aug 27, 12:54 pm, SimonPalmer <simon.pal...@g mail.comwrote:
On Aug 27, 12:50 pm, SimonPalmer <simon.pal...@g mail.comwrote:
On Aug 27, 12:41 pm, Jon Clements <jon...@googlem ail.comwrote:
On Aug 27, 12:29 pm, "Simon Brunning" <si...@brunning online.net>
wrote:
2008/8/27 SimonPalmer <simon.pal...@g mail.com>:
anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
len(list(csv.re ader(open('my.c sv'))))
--
Cheers,
Simon B.
si...@brunningo nline.nethttp://www.brunningonl ine.net/simon/blog/
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
Thanks to everyone for their suggestions.
In my case the number of rows is never going to be that large (<200)
so it is a practical if slightly inelegant solution
actually not resolved...
after reading the file throughthe csv.reader for the length I cannot
iterate over the rows. How do I reset the row iterator?
If you're sure that the number of rows is always less than 200.
Slightly modify Simon Brunning's example and do:
rows = list( csv.reader(open ('filename.csv' )) )
row_count = len(rows)
for row in rows:
# do something
On Aug 27, 9:54 pm, SimonPalmer <simon.pal...@g mail.comwrote:
On Aug 27, 12:50 pm, SimonPalmer <simon.pal...@g mail.comwrote:
On Aug 27, 12:41 pm, Jon Clements <jon...@googlem ail.comwrote:
On Aug 27, 12:29 pm, "Simon Brunning" <si...@brunning online.net>
wrote:
2008/8/27 SimonPalmer <simon.pal...@g mail.com>:
anyone know how I would find out how many rows are in a csv file?
I can't find a method which does this on csv.reader.
len(list(csv.re ader(open('my.c sv'))))
--
Cheers,
Simon B.
si...@brunningo nline.nethttp://www.brunningonl ine.net/simon/blog/
Not the best of ideas if the row size or number of rows is large!
Manufacture a list, then discard to get its length -- ouch!
Thanks to everyone for their suggestions.
In my case the number of rows is never going to be that large (<200)
so it is a practical if slightly inelegant solution
actually not resolved...
after reading the file throughthe csv.reader for the length I cannot
iterate over the rows.
OK, I'll bite: Why do you think you need to know the number of rows in
advance?
How do I reset the row iterator?
You don't. You throw it away and get another one. You need to seek to
the beginning of the file first. E.g.:
C:\junk>type foo.csv
blah,blah
waffle
q,w,e,r,t,y
C:\junk>type csv2iters.py
import csv
f = open('foo.csv', 'rb')
rdr = csv.reader(f)
n = 0
for row in rdr:
n += 1
print n, f.tell()
f.seek(0)
rdr = csv.reader(f)
for row in rdr:
print row
C:\junk>csv2ite rs.py
3 32
['blah', 'blah']
['waffle']
['q', 'w', 'e', 'r', 't', 'y']
HTH,
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