Question

I’m trying to use the csv module to read a utf-8 csv file, and I have some trouble to create a generic code for python 2 and 3 due to encoding.

Here is the original code in Python 2.7:

with open(filename, 'rb') as csvfile:
    csv_reader = csv.reader(csvfile, quotechar='\"')
    langs = next(csv_reader)[1:]
    for row in csv_reader:
        pass

But when I run it with python 3, it doesn’t like the fact that I open the file without “encoding”. I tried this:

with codecs.open(filename, 'r', encoding='utf-8') as csvfile:
    csv_reader = csv.reader(csvfile, quotechar='\"')
    langs = next(csv_reader)[1:]
    for row in csv_reader:
        pass

Now python 2 can’t decode the line in the “for” loop. So… how should I do it ?

Answer 1

Indeed, in Python 2 the file should be opened in binary mode, but in Python 3 in text mode. Also in Python 3 newline='' should be specified (which you forgot).

You’ll have to do the file opening in an if-block.

import sys

if sys.version_info[0] < 3: 
    infile = open(filename, 'rb')
else:
    infile = open(filename, 'r', newline='', encoding='utf8')


with infile as csvfile:
    ...