Get category count relative to the current query

Question

I am using WordPress and on the search page I need to grab the number of posts within the category and display it next to the name. Like so

Cat 1 (3) Cat 2 (1) Cat 3 (18) ....

Currently I am using the get_categories() functions which gives you an object and grabbing the count with $cat->count(). This grabs the total number of posts within the term but I need to grab that count only from the post within the current query. I am using pre_get_posts to update the query. Anybody know of a way to do this?

Here is my current code block

foreach ( get_categories() as $cat ) {
    if ( $cat->parent === 0 ) {
        $checked = ( in_array( $cat->slug, $check ) ) ? 'checked' : '';

        printf( '<input id="%1$s" %4$s type="checkbox" name="category[%1$s]"><label for="%1$s" >%2$s ( %3$d )</label><br>',
            $cat->slug,
            $cat->name,
            $cat->count,
            $checked
        );
    }
}

Here is my pre_get_posts action:

add_action( 'pre_get_posts', 'breed_search_query' );
function breed_search_query( $query ) {
$cats   = ( isset( $_GET['category'] ) ) ? implode( ',', array_keys( $_GET['category'] ) ) : null;
$search = ( isset( $_GET['s'] ) ) ? sanitize_text_field( $_GET['s'] ) : null;

    if ( ! is_admin() && $query->is_main_query() && is_search() ) {
        $query->set( 'post_type', 'post' );
        $query->set( 'posts_per_page', 8 );
        $query->set( 's', $search );
        $query->set( 'category_name', $cats );
    }
}

Answer 1

Nice and interesting question must say. Unfortunately, you are not going to get this to work with get_categories, so you will need another approach here.

Here is how we will do it:

• Create a very lean custom query to get all the post ID's from all posts matching the query

• Get all the categories attached to a post

• Loop through all the posts and the categories within the posts and build an array with the category names as keys and post ID's as values

• Loop through this new array, and display the category name and also count and display the amount of posts for that specific key ( category )

THE CODE:

(NOTE: The following code is untested and needs at leat PHP 5.4+ due to the new array syntax ([]))

$cats   = ( isset( $_GET['category'] ) ) ? implode( ',', array_keys( $_GET['category'] ) ) : null;
$search = ( isset( $_GET['s'] ) ) ? sanitize_text_field( $_GET['s'] ) : null;

$args = [
    'post_type'     => 'post',
    'nopaging'      => true, // Gets all posts
    's'             => $search,
    'category_name' => $cats,
    'fields'        => 'ids', // Makes the query extremely lean, excellent for performance, only get post ID's
];
$q = get_posts( $args );

// Define our $category_array which will hold the category name/post ID's array
$category_array = [];

// Define our $category_info array which will hold the category name as key and the object as value
$category_info = [];

foreach ( $q as $post ) {
    // Get the categories attached to a post
    $categories = get_the_category( $post );

    foreach ( $categories as $category ) {
        // Create our array which will hold the category name as key and post ID's as values
        $category_array[$category->name][] = $post;
        // Create an array to hold the category objects. Use names as keys and objects as values
        $category_info[$category->name] = $category;
    } // endforeach $categories
} // endforeach $wp_query->posts
wp_reset_postdata();

// Sort the array keys alphabetical. You can change or remove this as necessary
ksort( $category_array );

foreach ( $category_array as $k=>$v ) {

    $category_slug = $category_info[$k]->slug;
    $category_parent = $category_info[$k]->parent;

    $checked = ( in_array( $category_slug, $check ) ) ? 'checked' : ''; // Just make sure that $check is defined somewhere

    // Build our string
    printf ( '<input id="%1$s" %4$s type="checkbox" name="category[%1$s]"><label for="%1$s" >%2$s ( %3$d )</label><br>', // I have not modified anything in this line
        $category_slug, // Holds the category slug
        $k, // Holds the category name
        count( $v ), // Counts and return the post count
        $checked
    );
} // endforeach $category_array