diff options
-rw-r--r-- | NEWS | 6 | ||||
-rw-r--r-- | enum.c | 43 | ||||
-rw-r--r-- | test/ruby/test_enum.rb | 5 |
3 files changed, 54 insertions, 0 deletions
@@ -24,6 +24,12 @@ sufficient information, see the ChangeLog file or Redmine === Core classes updates (outstanding ones only) +Enumerable:: + + New method:: + + * Added Enumerable#tally. [Feature #11076] + === Stdlib updates (outstanding ones only) CSV:: @@ -935,6 +935,48 @@ enum_group_by(VALUE obj) return enum_hashify(obj, 0, 0, group_by_i); } +static void +tally_up(VALUE hash, VALUE group) +{ + VALUE tally = rb_hash_aref(hash, group); + if (NIL_P(tally)) { + tally = INT2FIX(1); + } + else if (FIXNUM_P(tally) && tally < INT2FIX(FIXNUM_MAX)) { + tally += INT2FIX(1) & ~FIXNUM_FLAG; + } + else { + tally = rb_big_plus(tally, INT2FIX(1)); + } + rb_hash_aset(hash, group, tally); +} + +static VALUE +tally_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, hash)) +{ + ENUM_WANT_SVALUE(); + tally_up(hash, i); + return Qnil; +} + +/* + * 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. + * + * (1..6).tally { |i| i%3 } #=> {0=>2, 1=>2, 2=>2} + * + */ + +static VALUE +enum_tally(VALUE obj) +{ + return enum_hashify(obj, 0, 0, tally_i); +} + static VALUE first_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, params)) { @@ -4070,6 +4112,7 @@ Init_Enumerable(void) rb_define_method(rb_mEnumerable, "reduce", enum_inject, -1); rb_define_method(rb_mEnumerable, "partition", enum_partition, 0); rb_define_method(rb_mEnumerable, "group_by", enum_group_by, 0); + rb_define_method(rb_mEnumerable, "tally", enum_tally, 0); rb_define_method(rb_mEnumerable, "first", enum_first, -1); rb_define_method(rb_mEnumerable, "all?", enum_all, -1); rb_define_method(rb_mEnumerable, "any?", enum_any, -1); diff --git a/test/ruby/test_enum.rb b/test/ruby/test_enum.rb index c56e280e06..1029143db6 100644 --- a/test/ruby/test_enum.rb +++ b/test/ruby/test_enum.rb @@ -294,6 +294,11 @@ class TestEnumerable < Test::Unit::TestCase assert_equal(h, @obj.each_with_index.group_by(&cond)) end + def test_tally + h = {1 => 2, 2 => 2, 3 => 1} + assert_equal(h, @obj.tally) + end + def test_first assert_equal(1, @obj.first) assert_equal([1, 2, 3], @obj.first(3)) |