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-rw-r--r--mrbgems/mruby-enum-ext/mrblib/enum.rb17
-rw-r--r--mrbgems/mruby-enum-ext/test/enum.rb5
2 files changed, 21 insertions, 1 deletions
diff --git a/mrbgems/mruby-enum-ext/mrblib/enum.rb b/mrbgems/mruby-enum-ext/mrblib/enum.rb
index e354a4c5e..178496e7e 100644
--- a/mrbgems/mruby-enum-ext/mrblib/enum.rb
+++ b/mrbgems/mruby-enum-ext/mrblib/enum.rb
@@ -839,4 +839,21 @@ module Enumerable
end
alias filter select
+
+ ##
+ # call-seq:
+ # enum.tally -> a_hash
+ #
+ # Tallys the collection. Returns a hash where the keys are the
+ # elements and the values are numbers of elements in the collection
+ # that correspond to the key.
+ #
+ # ["a", "b", "c", "b"].tally #=> {"a"=>1, "b"=>2, "c"=>1}
+ def tally
+ hash = {}
+ self.each do |x|
+ hash[x] = (hash[x]||0)+1
+ end
+ hash
+ end
end
diff --git a/mrbgems/mruby-enum-ext/test/enum.rb b/mrbgems/mruby-enum-ext/test/enum.rb
index 8c8daa678..f0301a2d9 100644
--- a/mrbgems/mruby-enum-ext/test/enum.rb
+++ b/mrbgems/mruby-enum-ext/test/enum.rb
@@ -189,7 +189,10 @@ assert("Enumerable#to_h") do
assert_equal({1=>4,3=>8}, c.new.to_h{|k,v|[k,v*2]})
end
-
assert("Enumerable#filter_map") do
assert_equal [4, 8, 12, 16, 20], (1..10).filter_map{|i| i * 2 if i%2==0}
end
+
+assert("Enumerable#tally") do
+ assert_equal({"a"=>1, "b"=>2, "c"=>1}, ["a", "b", "c", "b"].tally)
+end