PHP的foreach还有什么更优雅的写法？

Question

     $arr = [1,2,4];
     $arr_name = [];
     foreach ($arr_name as $key => $val) {
        if ($val == 1) {
            $arr_name[] = '小明';
        }else if ($val == 2) {
            $arr_name[] =  '小白';
        }else if ($val == 3) {
            $arr_name[] =  '小汪';
        }else if ($val == 4) {
            $arr_name[] =  '小哈';
        }
    }
    //得到结果是 $arr_name = ['小明','小白','小哈'];

还有没有其他写法？

Answer 1

<?php
// 1、使用数组键交集（缺陷，重复出现的搜寻不会出现）
// 映射关系
$arr1 = [1 => '小名', 2 => '小白', 3 => '小汪', 4 => '小哈'];
// 要搜寻的
$search = [1, 2, 3, 3, 4, 4, 4, 4,];
$tmp = array_fill_keys($search, '');

$rs = array_intersect_key($arr1, $tmp);

var_dump($rs);
/**
array(4) {
  [1] =>
  string(6) "小名"
  [2] =>
  string(6) "小白"
  [3] =>
  string(6) "小汪"
  [4] =>
  string(6) "小哈"
}
*/


// 2、先用数字和文本建立索引，然后使用 array_map 遍历
$rs2 = array_map(function ($item) use ($arr1) {
    return $arr1[$item] ?? $item;
}, $search);

var_dump($rs2);
/**
array(8) {
  [0] =>
  string(6) "小名"
  [1] =>
  string(6) "小白"
  [2] =>
  string(6) "小汪"
  [3] =>
  string(6) "小汪"
  [4] =>
  string(6) "小哈"
  [5] =>
  string(6) "小哈"
  [6] =>
  string(6) "小哈"
  [7] =>
  string(6) "小哈"
}
*/

Answer 2

$arr = [1,2,4];
$names = ['小明', '小白', '小汪', '小哈'];
$arr_name = array_map(function ($id) use ($names) {
  return $names[$id - 1];  
}, $arr);