What is an Illegal octal digit?

Question

I'm trying to make an array of zip codes.

array = [07001, 07920]

This returns :

array = [07001, 07920]
                  ^
    from (irb):12
    from :0

Never seen this before. Any workarounds?

Answer 1

Ruby is interpreting numbers that have a leading 0 as being in octal (base 8). Thus the digits 8 and 9 are not valid.

It probably makes more sense to store ZIP codes as strings, instead of as numbers (to avoid having to pad with zeroes whenever you display it), as such: array = ["07001", "07920"]