Adding variable number of zeroes to make a six digit number

Question

I am working with a membership database which records all accounts in a six digit format however, some users will be using a sub-six digit format due to older conventions. So I want to be able to accept a sub-six digit number and prefix zeroes to the beginning of it.

e.g. user enters number 1234, I want PHP to format it to become 001234. user enters number 123, I want PHP to format it to become 000123.

Answer 1

You can use PHPs sprintf()-function:

$formattedNumber = sprintf('%06d', $unformattedNumber);

Answer 2

Too Easy

str_pad($input, 6, "0", STR_PAD_LEFT);