diff options
| -rw-r--r-- | mrbgems/mruby-enum-ext/mrblib/enum.rb | 39 | ||||
| -rw-r--r-- | mrbgems/mruby-enum-ext/test/enum.rb | 4 |
2 files changed, 43 insertions, 0 deletions
diff --git a/mrbgems/mruby-enum-ext/mrblib/enum.rb b/mrbgems/mruby-enum-ext/mrblib/enum.rb index 873de1fbc..4b0b87bcc 100644 --- a/mrbgems/mruby-enum-ext/mrblib/enum.rb +++ b/mrbgems/mruby-enum-ext/mrblib/enum.rb @@ -374,4 +374,43 @@ module Enumerable end [min, max] end + + ## + # call-seq: + # enum.minmax_by { |obj| block } -> [min, max] + # enum.minmax_by -> an_enumerator + # + # Returns a two element array containing the objects in + # <i>enum</i> that correspond to the minimum and maximum values respectively + # from the given block. + # + # If no block is given, an enumerator is returned instead. + # + # %w(albatross dog horse).minmax_by { |x| x.length } #=> ["dog", "albatross"] + + def minmax_by(&block) + max = nil + max_cmp = nil + min = nil + min_cmp = nil + first = true + + self.each do |val| + if first + max = min = val + max_cmp = min_cmp = block.call(val) + first = false + else + if (cmp = block.call(val)) > max_cmp + max = val + max_cmp = cmp + end + if (cmp = block.call(val)) < min_cmp + min = val + min_cmp = cmp + end + end + end + [min, max] + end end diff --git a/mrbgems/mruby-enum-ext/test/enum.rb b/mrbgems/mruby-enum-ext/test/enum.rb index 2f7ed7aaa..4dfa2fec0 100644 --- a/mrbgems/mruby-enum-ext/test/enum.rb +++ b/mrbgems/mruby-enum-ext/test/enum.rb @@ -90,3 +90,7 @@ assert("Enumerable#minmax") do assert_equal ["albatross", "horse"], a.minmax assert_equal ["dog", "albatross"], a.minmax { |a, b| a.length <=> b.length } end + +assert("Enumerable#minmax_by") do + assert_equal ["dog", "albatross"], %w(albatross dog horse).minmax_by { |x| x.length } +end |