int format for 001 - 999

[snippsat]

I'm just looking for a way to count 001, 002 - 999.

Use string formatting f-string is what you should use need 3.6+,version before that use format().

for i in range(1,21):
    print(f"{i:03}") 

Output:
001
002
003
004
005
006
007
008
009
010
011
012
013
014
015
016
017
018
019
020