Reading from spreadsheet that is CSV and getting some unexpected empty lists

Question

SO here's the code -

import csv

with open('csv_example_files.csv') as csvfile:
    readCSV = csv.reader(csvfile , delimiter = ',')
    print(readCSV)
    for row in readCSV:
        print(row)

And the output is:

<_csv.reader object at 0x0000024D3DC42388>
['1/2/2014', '4', 'red']
['1/2/2014', '1', 'kv']
['1/2/2014', '1', 'jblock']
['1/3/2018', '1', 'kv']
['1/5/2114', '1', 'kv']
[]
[]
[]

I didn't expect the last 3 empty lists I don't know why they occurred so help me out. I am just a beginner and as I was following a tutorial series and I got stuck here.

Please edit your question and add a copy of the csv_example_files.csv file you're testing with. Also, in Python 3 you should add a newline='' keyword argument to the open() call. For Python 2, you need to add a mode argument after the file name argument of 'rb'. — martineau
– martineau, Commented Jan 4, 2018 at 16:16
If your CSV file contains blank lines, you could add if len(row) == 3: before your print statement to skip over them. — Martin Evans
– Martin Evans, Commented Jan 4, 2018 at 17:57

sophros · Accepted Answer · 2018-01-04 16:06:26Z

2

It is likely that your CSV file ends with 3 newlines. These result in empty lists when reading via csv module.

answered Jan 4, 2018 at 16:06

sophros

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Comments

Martin Evans · Accepted Answer · 2018-01-04 18:00:12Z

You are getting those extra lines as your CSV file contains blank lines. You can either edit the file and remove the blank lines, or alternatively add a test to make sure that the row contains the correct number of cells, e.g. 3:

import csv

with open('csv_example_files.csv', newline='') as f_input:
    csv_input = csv.reader(f_input)

    for row in csv_input:
        if len(row) == 3:
            print(row)

This should give you the following output:

['1/2/2014', '4', 'red']
['1/2/2014', '1', 'kv']
['1/2/2014', '1', 'jblock']
['1/3/2018', '1', 'kv']
['1/5/2114', '1', 'kv']

Note: The delimiter for a CSV file is already a ,. You should also add newline='' when using Python 3.x

Gianmar · Accepted Answer · 2018-01-04 16:23:09Z

-1

Try add csvfile.readline():

with open("csv_example_files.csv") as csvfile:
    csvfile.readline()
    readCSV = csv.reader(csvfile , delimiter = ',')
    print(readCSV)
    for row in readCSV:
        print(row)

Check this answers

answered Jan 4, 2018 at 16:23

Gianmar

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