How can I get the row count of a CSV file?

Question

fieldnames = ['first_name', 'last_name', 'address']
with open('names.csv') as csvfile:
    reader = csv.DictReader(csvfile, fieldnames=fieldnames)
    for row in reader:
        print(row['first_name'], "'s number", row['last_name'], "address", row['adres'])

This is my code to print my CSV file. If the CSV file is empty, I want to print that it's empty. I thought that if i can get the row count of the file, I can check if it's empty.

Possible duplicate of [Number of lines in csv.DictReader](https://stackoverflow.com/questions/2890549/number-of-lines-in-csv-dictreader) — Abhijeet, Jun 20 '17 at 11:49

score 10 · Answer 1 · answered Jan 09 '17 at 17:26

10

An efficient way to get row count using sum function(with a generator expression):

with open('names.csv') as csvfile:
    row_count = sum(1 for row in csvfile)
    print(row_count if row_count else 'Empty')

answered Jan 09 '17 at 17:26

RomanPerekhrest

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score 8 · Accepted Answer · answered Jan 09 '17 at 17:23

8

just do

len(list(reader))

it iterates through the reader object to create a list, then computes length & the number or rows is the list length (title not included)

note that this statement consumes the file, so store the list(reader) variable somewhere if you plan to parse the file.

answered Jan 09 '17 at 17:23

Jean-François Fabre

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In practice, I had to open file once to get row count, close it, open again and parse it normally. – Ezequiel Adrian May 25 '23 at 06:37
1

Yes it works, but it's much better to read the file once and store it in memory (unless the file is super huge and doesn't hold in memory) – Jean-François Fabre May 25 '23 at 07:12

score 0 · Answer 3 · answered Jan 09 '17 at 17:28

0

What about this :

import os
os.stat("names.csv").st_size == 0

Return true if it's empty, you want this right?

answered Jan 09 '17 at 17:28

1

if there's only a title line, that would fail. – Jean-François Fabre Jan 09 '17 at 17:37

score 0 · Answer 4 · answered Jan 09 '17 at 17:47

You could also enumerate the entries as you parse the file as follows:

fieldnames = ['first_name', 'last_name', 'address']

with open('names.csv') as csvfile:
    reader = csv.DictReader(csvfile, fieldnames=fieldnames)
    for count, row in enumerate(reader):
        print(row['first_name'], "'s number", row['last_name'], "address", row['address'])            

    if count == 0:
        print("empty")

How can I get the row count of a CSV file?

4 Answers4

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