method

group_by

v1_8_7_330 - Show latest stable - 1 note - Class: Enumerable

group_by() public

Returns a hash, which keys are evaluated result from the block, and values are arrays of elements in enum corresponding to the key.

(1..6).group_by {|i| i%3}   #=> {0=>[3, 6], 1=>[1, 4], 2=>[2, 5]}

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/*
 *  call-seq:
 *     enum.group_by {| obj | block }  => a_hash
 *
 *  Returns a hash, which keys are evaluated result from the
 *  block, and values are arrays of elements in <i>enum</i>
 *  corresponding to the key.
 *
 *     (1..6).group_by {|i| i%3}   #=> {0=>[3, 6], 1=>[1, 4], 2=>[2, 5]}
 *
 */

static VALUE
enum_group_by(obj)
    VALUE obj;
{
    VALUE hash;

    RETURN_ENUMERATOR(obj, 0, 0);

    hash = rb_hash_new();
    rb_block_call(obj, id_each, 0, 0, group_by_i, hash);

    return hash;
}

February 12, 2016

0 thanks

group on hash

‘

def group_by_hash hash, value
  hash.group_by do |k,v| 
    v > value ? "Big" : "Small"
  end
end

marks = {"Chair" => 30, "Table" => 40, "Bed" => 60, "stool" => 20}
group_by_hash(marks, 30)

group_by

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group on hash