New to Python

[Quin]

s = f.readline()
if 'mystring' in s: print 'foundit'
if 'mystring' not in s: print 'not found'
if 'mystring' in s:
    print 'processing'

this generates output:
not found
processing

so, it doesn't find the substring, but goes into processing code anyway.

This is using IronPython