Newbie question: replacing nulls in CSV with preceding value

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    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

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