PHP

drupal 8 user_load

function user_load($uid, $reset = FALSE) {
  if ($reset) {
    Drupal::entityManager()
      ->getStorage('user')
      ->resetCache(array(
      $uid,
    ));
  }
  return User::load($uid);
}

drupal 8 load user by name

$user = user_load_by_name('username');