How can I output leading zeros in Ruby?

Question

I\'m outputting a set of numbered files from a Ruby script. The numbers come from incrementing a counter, but to make them sort nicely in the directory, I\'d like to use leading

Answer 1

filenames = '000'.upto('100').map { |index| "file_#{index}" }

Outputs

[file_000, file_001, file_002, file_003, ..., file_098, file_099, file_100]