Read two csv files and compare every line. If the lines match print both lines, if it isn't similar print invalid

Question

import csv

f1 = open("file1.csv")

f2 = open("file2.csv")

csv_f1 = csv.reader(f1)

csv_f2 = csv.reader(f2)

for row1 in csv_f1: 
    for row2 in csv_f2:
        if row1 == row2:
            print row1[0], row2[0]
        else:
            print row1[0], "Invalid"

this program isn't printing out row1, row2. It's just printing first line of file1 and invalid on the same line several times.

Answer 1

You need to compare the corresponding rows, not each row with each row, which is what your code does right now.

from __future__ import print_function

import csv
import itertools
import sys

# Select the right function based on whether we are in Python 2 or 3.
if sys.version_info.major == 2:
    zip_longest = itertools.izip_longest
else:
    zip_longest = itertools.zip_longest

f1 = open("file1.csv")
f2 = open("file2.csv")

csv_f1 = csv.reader(f1)
csv_f2 = csv.reader(f2)

for row1, row2 in zip_longest(csv_f1, csv_f2):
    if row1 == row2:
        print(row1[0], row2[0])
    else:
        print(row1[0], "Invalid")