CODEWITHSUNDEEP
pythoncsv
Basj
Basj

Reputation: 46463

Delete some rows of a CSV, in-place

This:

import csv
with open('original.csv', 'rb') as inp, open('new.csv', 'wb') as out:
    writer = csv.writer(out)
    for row in csv.reader(inp):
        if row[2] != "0":
            writer.writerow(row)
os.remove('original.csv')
os.rename('new.csv', 'original.csv')

allows to delete certain rows of a CSV.

Is there a more pythonic way to delete some rows of a CSV file, in-place? (instead of creating a file, deleting the original, renaming, etc.)

Upvotes: 5

Views: 11469

Answers (2)

Andrew Lamarra
Andrew Lamarra

Reputation: 537

I noticed that your code does not import the os module, even though you're using it. Regardless, here's a method of doing what you need it to do without using that module.

This will open in read mode first to get the data, then write mode to overwrite. Note that you need to pass the csv.reader(f) statement to the list() function or else the data variable will simply point to the memory address of the CSV file and you won't be able to do anything with the content once it's closed. list() will actually copy the information for you.

import csv

with open("original.csv", "rb") as f:
    data = list(csv.reader(f))

with open("original.csv", "wb") as f:
    writer = csv.writer(f)
    for row in data:
        if row[2] != "0":
            writer.writerow(row)

Upvotes: 1

Ned Batchelder
Ned Batchelder

Reputation: 375574

There isn't a more Pythonic way: you can't delete stuff in the middle of a file. Write out a new file with the stuff you want, and then rename it.

Upvotes: 9

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