apsolut

<?php   //<- dont add me into functions.php 
/**
* Hide Gift Product Category from Shop
* https://wordpress.org/support/topic/hide-gift-product-category-from-shop/
* Create category Exclude or Gifts 
* Category slug: exclude, gifts
* add gifts that you want to exclude from shop archive to this category
*/

add_action( 'woocommerce_product_query', 'giftable_custom_pre_get_posts_query' );

igorbenic

<?php

add_filter( 'posts_clauses', 'filter_clauses', 10, 2 );

/**
 * Filtering everything.
 *
 * @param array $clauses Array with all parts of the query.
 * @param WP_Query $wp_query Object.
 * @return string

josanua

<?php 
// General info
https://codex.wordpress.org/Theme_Development

// Core info
https://wp-learner.com/wotdpress-development/wordpress-core-files-and-functions/

// Theme Handbook
https://developer.wordpress.org/themes/ 

wpadmin

<?php
/**
 * WooCommerce 3.3 - Hide uncategorized category from the shop page on the frontend and Remove Categories from WooCommerce Product Category Widget
 */
add_filter( 'woocommerce_product_subcategories_args', 'krs_remove_uncategorized_category' );
add_filter( 'woocommerce_product_categories_widget_args', 'krs_remove_uncategorized_category' );
add_filter( 'woocommerce_product_categories_widget_dropdown_args', 'krs_remove_uncategorized_category' );
add_filter( 'ywcca_wc_product_categories_widget_args', 'krs_remove_uncategorized_category' );

function krs_remove_uncategorized_category( $args ) {

fuyuko

//Add a stylesheet after default style.css
wp_enqueue_style( 'my-css',  get_template_directory_uri() . 'my-css.css', array('themename-style'));

//WooCommerce - Sort products by SKU
add_filter('woocommerce_get_catalog_ordering_args', 'custom_woocommerce_catalog_orderby');
function custom_woocommerce_catalog_orderby( $args ) {
    $args['meta_key'] = '_sku';
    $args['orderby'] = 'meta_value';
    $args['order'] = 'asc'; 
    return $args;