Newbie question: replacing nulls in CSV with preceding value

[Matt Waite]

Thanks everyone for your help. I got Skip's answer to work (mine is
pasted below):

import sys
import csv

last = {}
reader = csv.DictReader(open("/home/mwaite/test/test2.csv", "rb"))
writer = csv.DictWriter(open("/home/mwaite/test/test3.csv", "wb"),
['ZONE','CITY','EVENT'], dialect='excel')
for row in reader:
        for key in row:
            if not row[key]:
                row[key] = last.get(key, "")
        writer.writerow(row)
        last = row


On Feb 1, 3:37 pm, s... at pobox.com wrote:
>     Matt> I have a CSV file, exported from Excel, that has blank records in
>     Matt> it, and I need to fill them in with the values from the record
>     Matt> just above it until it hits a non-blank value.
>
> Try something like:
>
>     #!/usr/bin/env python
>
>     import sys
>     import csv
>
>     last = {}
>     reader = csv.DictReader(open("test1.csv", "rb"))
>     writer = csv.DictWriter(open("test2.csv", "wb"),
>                             sys.stdout, fieldnames="Zone City Event".split())
>     for row in reader:
>         for key in row:
>             if not row[key]:
>                 row[key] = last.get(key, "")
>         writer.writerow(row)
>         last = row
>
> Skip