Import a csv file to a list of lists

Question

I have this csv file created using writerow function from the csv module. The file has 63 lines. I want to create a list of lists in python from this file.

I tried the following code:

import csv

dataset = []

def importCsv(file):
    x = 0
    print(dataset)
    with open(file, newline='') as csvfile:
        data = csv.reader(csvfile, delimiter=',', quotechar='|')
        for row in data:
            #print(type(row))
            dataset.append(row)
            x += 1
        print(x)

importCsv(csvPath)

But when I try print(len(dataset)), it outputs 126 instead of 63. I am really confused. Why is the number of items in dataset so high?

Try printing `row` inside the `for` loop to see what is being added to `dataset` — Patrick Haugh, Jul 06 '18 at 15:22
126 = 63*2. Make sure that your file doesn't have spurious CR (carriage return) chars (the infamous windows CSV write bug) which makes a blank line after every line. — Jean-François Fabre, Jul 06 '18 at 15:31
if `open(file, "w",newline='')` (newline it is): if newline is omitted, then the bug occurs on windows: extra blank line after each line — Jean-François Fabre, Jul 06 '18 at 15:33
The problem is the input file. Check it with a hex editor and make sure the line endings aren't `\r\r\n` instead of `\n` or `\r\n`. — Mark Tolonen, Jul 06 '18 at 15:40

Sunitha · Answer 1 · 2018-07-06T16:54:38.580

1

The problem is mostly due to spurious CarriageReturn \r chars, causing some empty rows to appear. You can skip empty rows by adding an explicit check

    for row in data:
        if row:
            dataset.append(row)
            x += 1

edited Jul 06 '18 at 16:54

answered Jul 06 '18 at 15:46

Sunitha

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`row` isn't a string, but it's a list. the issue is in the input file. – Jean-François Fabre Jul 06 '18 at 15:51
@Jean-FrançoisFabre. You are right... I have updated the answer – Sunitha Jul 06 '18 at 16:55

Import a csv file to a list of lists

1 Answers1