On Sep 5, 10:26 pm, planetmatt <[EMAIL PROTECTED]> wrote: > On 5 Sep, 12:34, John Machin <[EMAIL PROTECTED]> wrote: > > > > > On Sep 5, 8:58 pm, planetmatt <[EMAIL PROTECTED]> wrote: > > > > I am a Python beginner. I am trying to loop through a CSV file which > > > I can do. What I want to change though is for the loop to start at > > > row 2 in the file thus excluding column headers. > > > > At present I am using this statement to initiate a loop though the > > > records: > > > > for line in f.readlines(): > > > > How do I start this at row 2? > > > The quick answer to your literal question is: > > for line in f.readlines()[1:]: > > or, with extreme loss of elegance, this: > > for lino, line in enumerate(f.readlines()): > > if not lino: > > continue > > > But readline and readlines are old hat, and you wouldn't want to read > > a file of a few million lines into a big list, so a better answer is: > > > _unused = f.next() > > for line in f: > > > But you did say you were reading a CSV file, and you don't really want > > to do your own CSV parsing, even if you think you know how to get it > > right, so best is: > > > import csv > > rdr = csv.reader(f) > > heading_row = rdr.next() > > for data_row in rdr: > > > HTH, > > John > > Thanks so much for the quick response. All working now. > > I had looked at the CSV module but when I ran into another problem of > trying to loop through all columns, I was given a solution in another > forum which used the readlines() method.
Antique advice which still left you doing the CSV parsing :-) > > I have looked at the CSV documentation but didn't see any mention of > heading_row or data_row. Ummm ... 'heading_row' and 'data_row' are identifiers of the kind that you or I would need to make up in any language; why did you expect to find them in the documentation? > Is there a definitive Python documentation > site with code examples like MS's MSDN? The definitive Python documentation site is (I suppose) http://www.python.org/doc/ I don't know what "code examples like MS's MSDN" means. I avoid MSDN like I'd avoid a nurse carrying a bottle of Dettol and a wire brush :-) Here's an example of sucking your data into a list of lists and accessing it columnwise: rdr = csv.reader(f) whatever_you_want_to_call_the_heading_row = rdr.next() data = list(rdr) sum_col_5 = sum(float(row[5]) for row in data) print "The value in row 3, column 4 is", data[3][4] HTH, John -- http://mail.python.org/mailman/listinfo/python-list
