src/Types.php
public static function isList($array)
    {
        if (!is_array($array)) {
            return false;
        }

        $expected = 0;
        foreach ($array as $key => $unused) {
            if ($key !== $expected++) {
                return false;
            }
        }
        return true;
    }
public static function isList($array)
    {
        if (!is_array($array)) {
            return false;
        }

        $expected = 0;
        foreach ($array as $key => $unused) {
            if ($key !== $expected++) {
                return false;
            }
        }
        return true;
    }
Checks whether the given argument is a list (vector array)

An empty array is considered both a list and a map.

@param mixed $array
@return bool