Reading from CSVs in Python repeatedly?

24
votes

I'm trying to check the value of extracted data against a csv I already have. It will only loop through the rows of the CSV once, I can only check one value of feed.items(). Is there a value I need to reset somewhere? Is there a better/more efficient way to do this? Thanks.

orig = csv.reader(open("googlel.csv", "rb"), delimiter = ';')
goodrows = []
for feed in gotfeeds:    
   for link,comments in feed.items():
       for row in orig:
           print link
           if link in row[1]:
               row.append(comments)
               goodrows.append(row)
2
pythoncsv

2 Answers

38
votes

You can "reset" the CSV iterator by resetting the read position of the file object.

data = open("googlel.csv", "rb")
orig = csv.reader(data, delimiter = ';')
goodrows = []
for feed in gotfeeds:    
   for link,comments in feed.items():
       data.seek(0)
       for row in orig:
           print link
           if link in row[1]:
               row.append(comments)
               goodrows.append(row)
13
votes

Making orig a list avoids the need to reset/reparse the csv:

orig = list(csv.reader(open("googlel.csv", "rb"), delimiter = ';'))