Sometimes we receive this c(1, 22, 131) and we need character
variables of the same size, such as c("001", "022", "131"). This
happens if a user has mistakenly converted a zip code (US regional
identifier) like "00231" to a number. This function converts the
number back to a 0 padded string.
This works differently if the number provided is an integer, or a
character string. Integers are left padded with the character
"0". A character string will be left-padded with blanks.