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) {
    return $num % 2 == 0;
});
// => [2,4,6]
where:
$people = [['name' => 'Jack Nicholson', 'born' => 1937, 'profession' => 'actor'], ['name' => 'Morgan Freeman', 'born' => 1937, 'profession' => 'actor'], ['name' => 'Leonardo Dicaprio', 'born' => 1974, 'profession' => 'actor'], ['name' => 'Nathalie Portman', 'born' => 1981, 'profession' => 'actor'], ['name' => 'Ridley Scott', 'born' => 1937, 'profession' => 'producer']];
$actorsBornIn1937 = _::where($people, ['born' => 1937, 'profession' => 'actor']);
// => Jack Nicholson & Morgan Freeman
findWhere:
$people = [['name' => 'Jack Nicholson', 'born' => 1937, 'profession' => 'actor'], ['name' => 'Morgan Freeman', 'born' => 1937, 'profession' => 'actor'], ['name' => 'Leonardo Dicaprio', 'born' => 1974, 'profession' => 'actor'], ['name' => 'Nathalie Portman', 'born' => 1981, 'profession' => 'actor'], ['name' => 'Ridley Scott', 'born' => 1937, 'profession' => 'producer']];
$actor = _::findWhere($people, ['born' => 1937, 'profession' => 'actor']);
// => Jack Nicholsonn
reject:
$odds = _::reject([1, 2, 3, 4, 5, 6], function ($num) {
    return $num % 2 == 0;
});
// => [1,3,5]
every:
_::every([true, 1, null, 'yes']);
// => false
some:
_::some([null, 0, 'yes', false]);