Searching for a string in a large text file - profiling various methods in python

Question

This question has been asked many times. After spending some time reading the answers, I did some quick profiling to try out the various methods mentioned previously...

Answer 1

You could also try

with open('input.txt') as f:
    # search_str is matched against each line in turn; returns on the first match:
    print search_str in f

with search_str ending with the proper newline sequence('\n' or '\r\n'). This should use little memory, as the file is read progressively. It should also be quite fast, since only part of the file is read.