src/Utility/ArrayUtil.php
public static function isAssociateArray(array $arr)
    {
        if (!empty($arr)) {
            foreach ($arr as $k => $v) {
                if (is_int($k)) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }
public static function isAssociateArray(array $arr)
    {
        if (!empty($arr)) {
            foreach ($arr as $k => $v) {
                if (is_int($k)) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }
Test if an array is an associate array

@param array $arr
@return true if $arr is an associative array