}); // => displays each pair in turn eachReference: $numbers = [1, 2, 3]; _::eachReference($numbers, function (&$value) { $value *= $value; }); // => [1,4,9] map: _::map([1, 2, 3], function ($value) { return $value - 1; }); // => [0,1,2] reduce: $sum = _::reduce([1, 2, 3], function ($memo, $num) { return $memo + $num; }, 0); // => 6 reduceRight: $list = [[0, 1], [2, 3], [4, 5]]; $flat = _::reduceRight($list, function ($a, $b) { return array_merge($a, $b); }, []); // => [4,5,2,3,0,1] find: $even = _::find([1, 2, 3, 4, 5, 6], function ($num) { return $num % 2 == 0; }); // => 2 filter: $evens = _::filter([1, 2, 3, 4, 5, 6], function ($num) {