Python: Iterate a certain number of times without storing the iteration number anywhere

Question

Hello...

I was wondering if it is possible to perform a certain number of operations without storing the loop iteration number anywhere.

For instance, let's say I want to print two "hello" messages on the console. Right now I know I can do:

for i in range(2):
    print "hello"

but then the "i" variable is going to take the values 0 and 1 (which I don't really need). Is there a way to achieve the same thing without storing that anywhere?

I know it's not big deal... I'm just curious :-)

Thank you in advance

Answer 1

The idiom (shared by quite a few other languages) for an unused variable is a single underscore _. Code analysers typically won't complain about _ being unused, and programmers will instantly know it's a shortcut for i_dont_care_wtf_you_put_here. There is no way to iterate without having an item variable - as the Zen of Python puts it, "special cases aren't special enough to break the rules".

Answer 2

for word in ['hello'] * 2:
    print word

It's not idiomatic Python, but neither is what you're trying to do.

Answer 3

exec 'print "hello";' * 2

should work, but I'm kind of ashamed that I thought of it.

Update: Just thought of another one:

for _ in " "*10: print "hello"

Answer 4

Although I agree completely with delnan's answer, it's not impossible:

loop = range(NUM_ITERATIONS+1)
while loop.pop():
    do_stuff()

Note, however, that this will not work for an arbitrary list: If the first value in the list (the last one popped) does not evaluate to False, you will get another iteration and an exception on the next pass: IndexError: pop from empty list. Also, your list (loop) will be empty after the loop.

Just for curiosity's sake. ;)