Catching an exception while using a Python 'with' statement

Question

To my shame, I can't figure out how to handle exception for python 'with' statement. If I have a code:

with open("a.txt") as f:     print f.readlines() 

I really want to handle 'file not found exception' in order to do somehing. But I can't write

with open("a.txt") as f:     print f.readlines() except:     print 'oops' 

and can't write

with open("a.txt") as f:     print f.readlines() else:     print 'oops' 

enclosing 'with' in a try/except statement doesn't work else: exception is not raised. What can I do in order to process failure inside 'with' statement in a Pythonic way?

Answer 1

from __future__ import with_statement  try:     with open( "a.txt" ) as f :         print f.readlines() except EnvironmentError: # parent of IOError, OSError *and* WindowsError where available     print 'oops' 

If you want different handling for errors from the open call vs the working code you could do:

try:     f = open('foo.txt') except IOError:     print('error') else:     with f:         print f.readlines()