How to search for a string case-insensitively without regular expressions?

Question

I want to search a file for all lines containing a given string without matching case. How can I make this code case-insensitive?

Answer 1

with open(logfile) as fin:
    for line in fin:
        if var.lower() in line.lower():  # makes this case insensitive
            print 'found', line.rstrip() # You will be printing double new lines 
                                         #  without rstrip here