What is the easiest way to iterate through files while maintaining a counter?

Question

What is the cleanest code iterating through the lines of a text file while increasing the counter?

I understand that with multiple assignment there is a cleaner syntax than

i = 0 for line in f: ... ++i 

Answer 1

 for i, line in enumerate(f): print i, line 

As shown here: http://docs.python.org/library/functions.html#enumerate

Answer 2

 for count, line in enumerate(f): 

Enumeration starts at index 0, unless otherwise specified, provided that the counter is repeated at the same time as each element of the for loop

EDIT: as a side note, you can change where the enumeration starts with the second argument, for example. for count, line in enumerate(f, 11) will cause it to start at 11