checking input output files existence inpython code example

Example 1: python os if file exists

import os.path

if os.path.isfile('filename.txt'):
    print ("File exist")
else:
    print ("File not exist")

Example 2: check if a file exists

>>> import os
>>> os.path.isfile("d:\\Package1\\package1\\fibo.py")
True
>>> os.path.isfile("d:/Package1/package1/fibo.py")
True
>>> os.path.isfile("d:\\nonexisting.txt")