core/Form.php
public function removeField(string $name)
    {
        $field = isset($this->fields[$name]) ? $this->fields[$name] : null;
        if ($field !== null) {
            unset($this->fields[$name]);
        }
        return $field;
    }
public function removeField(string $name)
    {
        $field = isset($this->fields[$name]) ? $this->fields[$name] : null;
        if ($field !== null) {
            unset($this->fields[$name]);
        }
        return $field;
    }
删除字段
@param string $name
@return Field|null