List all-childpages on parent-page AND list child-pages on childpage itself but not the current one?

Question

I have the following function that lists all Child-Pages of a page.

function show_subpages() {

    global $post;
    $subpages = wp_list_pages( array(
        'echo'          =>0,
        'title_li'      =>'',
        'depth'         =>2,
        'link_before'   => '— ',
        'child_of'      => ( $post->post_parent == 0 ? $post->ID : $post->post_parent)
    ));
    if ( !empty($subpages) ) {
        echo '<ul id="subpages" class="wrapper">';
        echo $subpages;
        echo '</ul>';
    }
}

So when I'm on the parent-page I see a list with all the child-pages. If I'm on a child-page I see the same list with all the child-pages corresponding with the parent-page.

— My Parent Page
   — My Child Page Nr. 1
   — My Child Page Nr. 2
   — My Child Page Nr. 3

This is almost what I want! The only little thing I need to add is to remove the "current" page I'm on from the list of child-pages.

So imagine I'm on My Child Page Nr. 2 I only want to list My Child Page Nr. 1 and My Child Page Nr. 3 but not "Nr. 2" since I'm currently on this one.

Any ideas how to add this?

Thank you in advance.

Answer 1

function show_subpages() {

    global $post;
    $subpages = wp_list_pages( array(
        'echo'          =>0,
        'title_li'      =>'',
        'depth'         =>2,
        'link_before'   => '— ',
        'child_of'      => ( $post->post_parent == 0 ? $post->ID : $post->post_parent),
        'exclude'       => ( $post->post_parent == 0 ? '' : $post->ID)
    ));
    if ( !empty($subpages) ) {
        echo '<ul id="subpages" class="wrapper">';
        echo $subpages;
        echo '</ul>';
    }
}

wp_list_pages supports an exclude parameter. In the above, I've simply added 'exclude' => ( $post->post_parent == 0 ? '' : $post->ID) to the parameter array.
It works analogous to the way you are already feeding values to child_of:
If the post does not have a parent, we feed exclude an empty string. If it has one, we feed it the current post ID.