how change mysql hostname from "db" to "localhost"

hello this work now $mysqli = new mysqli("db","wordpress","wordpress","wordpress"); how i can change it to so that work $mysqli = new mysqli("localhost","wordpress","wordpress","wordpress");

docker-comose.yml

version: '3'

services:
  # Database
  db:
    image: mysql:5.7
    volumes:
      - db_data:/var/lib/mysql
    restart: unless-stopped
    environment:
      MYSQL_ROOT_PASSWORD: password
      MYSQL_DATABASE: wordpress
      MYSQL_USER: wordpress
      MYSQL_PASSWORD: wordpress
    networks:
      - wpsite
  # phpmyadmin
  phpmyadmin:
    depends_on:
      - db
    image: phpmyadmin
    restart: always
    ports:
      - '8080:80'
    environment:
      MYSQL_ROOT_PASSWORD: password
    networks:
      - wpsite
  # Wordpress
  wordpress:
    depends_on:
      - db
    image: wordpress:latest
    ports:
      - '8000:80'
    restart: always
    volumes: ['./:/var/www/html']
    environment:
      WORDPRESS_DB_HOST: db:3306
      WORDPRESS_DB_USER: wordpress
      WORDPRESS_DB_PASSWORD: wordpress
    networks:
      - wpsite



networks:
  wpsite:
volumes:
  db_data: