我想您正在寻找PHP函数extract()

function your_shortcode_callback( $atts ) {

    // compare incoming $atts against defaults and extract out 
    extract( shortcode_atts( array(
        \'width\'         => \'12\',
        \'height\'        => \'4\',
        \'file\'      => \'\'
    ), $atts ) );

    if( ! $file )
        return \'\';

    // do something with the $width, $height, and $file variables

}