Exclude non alphanumeric characters

Hi,

Each item in the list is passed through a filter called a_z_listing_item_index_letter which allows you to change the detected index letter. For this example you can do something like below:

<?php
add_filter( 'a_z_listing_item_index_letter', 'ignore_quotes_in_a_z' 10, 3 );
function ignore_quotes_in_a_z( $indices, $item, $item_type ) {
    $title = get_the_title( $item );
    for ( $i = 0; $i < strlen( $title ); $i++ ) {
        $letter = substr( $title, $i, 1 );
        switch ( $letter ) {
            // add all the characters you want to ignore here - switch falls-through
            // so if any one of these are matched we hit the break; and continue
            // to the next letter in the title.
            case '"':
            case '\'':
            case '(':
            case '[':
                break;
            // if none of the above match then we use the character as the index
            default:
                return [ $letter ];
        }
    }

    // This is here to handle the case of the above code not giving an index
    return $indices;
}

Hi there,

Thanks for the answer.

It works, but not as expected, all accented characters (ááééííóó????úúüü??) went under #

I added some characters to the alphabet with the following code, it worked fine until now.

add_filter( 'a-z-listing-alphabet', 'add_hun');
function add_hun( $alphabet ) {
  return 'Aáà??aáà?a,Bb,C?c?,Dd,Eéè?êeéè?ê,Ff,Gg,Hh,Iíì??iíì??,Jj,Kk,Ll,Mm,Nn,Oóò???oóò???,Pp,Qq,Rr,Ss?,Tt,Uúùü??uúùü??,Vv,Ww,Xx,Yy,Zz';
}

Thanks

with mb_substr() instead of substr() works great, thanks!