CSV variable seems to reset

[marc wyburn]

Hi, I'm using the CSV module to parse a file using

whitelistCSV_file = open("\\pathtoCSV\\whitelist.csv",'rb')
whitelistCSV = csv.reader(whitelistCSV_file)
for uname, dname, nname in whitelistCSV:
print uname, dname, nname

The first time I run the for loop the contents of the file is
displayed. Subsequent attempts to run the for loop I don't get any
data back and no exception.

The only way I can get the data is to run whitelistCSV_file = open("\
\pathtoCSV\\whitelist.csv",'rb') again.

I'm stumped as to how I can get around this or work out what the
problem is, I'm assuming that the 'open' command buffers the data
somewhere and that data is being wiped out by the CSV module but
surely this shouldn't happen.

thanks, Marc.

[Tim Golden]

marc wyburn wrote:

Hi, I'm using the CSV module to parse a file using

whitelistCSV_file = open("\\pathtoCSV\\whitelist.csv",'rb')
whitelistCSV = csv.reader(whitelistCSV_file)
for uname, dname, nname in whitelistCSV:
print uname, dname, nname

The first time I run the for loop the contents of the file is
displayed. Subsequent attempts to run the for loop I don't get any
data back and no exception.

That's because the csv reader object is an iterator. You're
consuming it as you run through it. If you want to keep hold
of the contents to run again (without reinitialising it) then
pull the data into a list and iterate over that as many times
as you like:

data = list (whitelistCSV)
for uname, dname, nname in data:
# do stuff

for uname, dname, nname in data:
# do stuff again

TJG