In Python, is there a concise way of comparing whether the contents of two text files are the same?

Question

I don't care what the differences are. I just want to know whether the contents are different.

Answer 1

The low level way:

from __future__ import with_statement with open(filename1) as f1:    with open(filename2) as f2:       if f1.read() == f2.read():          ... 

The high level way:

import filecmp if filecmp.cmp(filename1, filename2, shallow=False):    ... 

Answer 2

If you're going for even basic efficiency, you probably want to check the file size first:

if os.path.getsize(filename1) == os.path.getsize(filename2):   if open('filename1','r').read() == open('filename2','r').read():     # Files are the same. 

This saves you reading every line of two files that aren't even the same size, and thus can't be the same.

(Even further than that, you could call out to a fast MD5sum of each file and compare those, but that's not "in Python", so I'll stop here.)