I want to find the corresponding hash in an array from a string that contains a criterion defined in a hash of the array.

I do something like that :

types = [
 {key: 'type_1', criteria: ['type_1a', 'type_1b']},
 {key: 'type_2', criteria: ['type_2a', 'type_2b']},

def find_type(str)
  types.each do |type|
    type[:criteria].each do |criterion|
      return type if str =~ /#{criterion}/i

I'm sure it could be more ruby but don't find how...


The orthodox (and functional) approach in Ruby is:

def find_type(types, str)
  types.detect do |type|
    type[:criteria].any? do |criterion|
      str =~ /#{criterion}/i # or Regexp.new(criterion, "i")
  • \$\begingroup\$ To guard against the possibility that any of the hashes to not have the key :criteria, you may want to replace h[:criteria] with (h[:criteria] || []). \$\endgroup\$ – Cary Swoveland Apr 30 '14 at 5:21
  • \$\begingroup\$ You forgot that the method needs types as an argument. I'll be deleting this comment... \$\endgroup\$ – Cary Swoveland Apr 30 '14 at 5:22
  • \$\begingroup\$ I guess types was not really a local variable but something accessible by the method. Anyway, added as an argument. \$\endgroup\$ – tokland Apr 30 '14 at 8:45

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