用 PHP 中更高效的东西替换嵌套的 foreach 循环

Question

我有两个数组，每个都有不同的结构：

$websites = Array (
     [1131] => Array (
          [httpcode] => 403
          [user_id] => 265
     )

     [1130] => Array (
          [httpcode] => 403
          [user_id] => 265
     )
)

$responses = Array (
     [1131] => 200
     [1130] => 500
)

我正在使用嵌套的 foreach 循环将 $websites 数组中的 httpcode 替换为 $responses 数组中相应的新 httpcode：

foreach ($websites as $site_id => &$details) {
    foreach ($responses as $resp_id => $new_http)  {
        if ($site_id == $resp_id) {
            $details['httpcode'] = $new_http;
        }  
    }        
}

此操作成功，我得到了正确的结果：

$websites = Array (
     [1131] => Array (
          [httpcode] => 200
          [user_id] => 265
     )

     [1130] => Array (
           [httpcode] => 500
           [user_id] => 265
     )
)

但是，我知道嵌套的 foreach 循环在 CPU 循环中的成本很高，我想知道是否有更有效的方法对大型数组执行此操作以最小化 CPU 在服务器上使用。

Answer 1

第二个循环完全没有意义。这就足够了：

foreach ($websites as $site_id => &$details) {
    $details['httpcode'] = $responses[$site_id];
}

如果两个数组可能不同步，您需要添加额外的密钥检查：

foreach ($websites as $site_id => &$details) {
    if (array_key_exists($site_id, $responses)) {
        $details['httpcode'] = $responses[$site_id];
    }
}

Answer 2

如果数组键相同：

foreach(array_keys($websites) as $key) {
  $websites[$key]['httpcode'] = $responses[$key];
}

用 PHP 中更高效的东西替换嵌套的 foreach 循环

Replacing a nested foreach loop with something more efficient in PHP

php

arrays

performance

foreach

processing-efficiency