How to read a file in reverse order?

Question

How to read a file in reverse order using python? I want to read a file from last line to first line.

Answer 1

a simple function to create a second file reversed (linux only):

import os
def tac(file1, file2):
     print(os.system('tac %s > %s' % (file1,file2)))

how to use

tac('ordered.csv', 'reversed.csv')
f = open('reversed.csv')