reformat string with regex

format_string_with_regex.rb

# Usage: 
#   tested with 8, 9, 10, 11, 12 digit phone numbers
#
#   ar = ["(+1) 888 33x19", "95606 3354", "555 123 1234", "0 95606 33544", "(+91) 95606 33544"]
#   ar.map {|e| format_string(e) }
#     => ["188-833-19", "956-063-354", "555-123-12-34", "095-606-335-44", "919-560-633-544"]
#
def format_string(s)
  # step #1 => remove all non-digits
  # step #2(a) => pick the digits in groups of 333[2][2]
  # step #2(b) => place the groups as 3-3-3-2-2
  # step #3 => replace any consecutive '-'(es) with a single '-'
  # 
  s.gsub(/[^0-9]/,'').gsub(/(...)(...)(...)?(..)?(..)/,'\1-\2-\3-\4-\5').gsub(/\-+/, '-')
end

# Note: I solved this as a challenge somewhere. Seemed interesting enough to share with fellow rubyists.