src/collections/Collection.php
public function getKeys($value, int $limit = 0): array
	{
		$predicate = function ($v, $k) use ($value)
		{
			return ($v === $value);
		};
		
		return $this->find($predicate, true, $limit);
	}
public function getKeys($value, int $limit = 0): array
	{
		$predicate = function ($v, $k) use ($value)
		{
			return ($v === $value);
		};
		
		return $this->find($predicate, true, $limit);
	}
public function getKeys ( $ value , int $ limit = 0 ) : array { $ predicate = function ( $ v , $ k ) use ( $ value ) { return ( $ v === $ value ) ; } ; return $ this -> find ( $ predicate , true , $ limit ) ; }
Get all keys of a given value.

@param mixed $value : the value whose keys to get
@param int $limit : the maximum amount of keys to get; 0 - no limit, negative value - get the last N keys
@return array an array containing all keys that were found
Get all keys of a given value .