Padding zeroes to left of string (python)?

Question

The length of the string needs to be 5 characters. When the string is "1" it needs to be returned as "00001", when the string is "10" it needs to be returned as "00010" and so on. I'm wondering how to do this using loops?

Have you thought using some of the `str` method. The docs have some really good examples and they provide lots of insight. — Zizouz212, Apr 14 '15 at 02:14
Such as [`format`](https://docs.python.org/3/library/functions.html#format) and its [spec](https://docs.python.org/3/library/string.html#formatspec). — TigerhawkT3, Apr 14 '15 at 02:15

score 1 · Answer 1 · answered Apr 14 '15 at 02:16

If you want to use for-loops, you can solve the problem like so:

def addPadding(str):
    output = ''
    # Prepend output with 0s
    for i in range(5 - len(str)):
        output += '0'
    output += str
    return output

print(addPadding('10'))
>> 00010
print(addPadding('1'))
>> 00001

score 0 · Answer 2 · answered Apr 14 '15 at 02:15

If you can't use string formatting or arrays or anything besides integer operators, you should be able to figure it out using division and a loop.

Is 10 divisible by 10000? Is 10 divisible by 1000? Is 10 divisible by 100? etc.

Try typing 10/10000 in your python interpreter. What's the result? :)

Padding zeroes to left of string (python)?

2 Answers2