framework/validators/RegularExpressionValidator.php
protected function validateValue($value)
    {
        $valid = !is_array($value) &&
            (!$this->not && preg_match($this->pattern, $value)
            || $this->not && !preg_match($this->pattern, $value));

        return $valid ? null : [$this->message, []];
    }
protected function validateValue($value)
    {
        $valid = !is_array($value) &&
            (!$this->not && preg_match($this->pattern, $value)
            || $this->not && !preg_match($this->pattern, $value));

        return $valid ? null : [$this->message, []];
    }
{@inheritdoc}