下面的解决方案将解析传递给短代码的逗号分隔值type 参数我们还将去掉值周围的空白，这是一种可用性改进（请参见下面代码后面的示例2）。

add_shortcode( \'related\', \'wpse_related\' );
function wpse_related( $atts, $content = \'\' ) {
    // User provided values are stored in $atts.
    // Default values are passed to shortcode_atts() below.
    // Merged values are stored in the $a array.
    $a = shortcode_atts( [
                \'type\'   => false,
    ], $atts );

    $output = \'\';

    if ( $a[\'type\'] ) {
        // Parse type into an array. Whitespace will be stripped.
        $a[\'type\'] = array_map( \'trim\', str_getcsv( $a[\'type\'], \',\' ) );
    }

    // Debugging: Display the type parameter as a formatted array.
    $output .= \'<pre>\' . print_r( $a[\'type\'], true  ) . \'</pre>\';

    return $output;
}

Example 1:

[related type="2,3,4,5,6"]

Output:

Array
(
    [0] => 2
    [1] => 3
    [2] => 4
    [3] => 5
    [4] => 6
)

Example 2:

[related type="8, 6, 7,5,30, 9"]

Output:

Array
(
    [0] => 8
    [1] => 6
    [2] => 7
    [3] => 5
    [4] => 30
    [5] => 9
)