Php 2个用于嵌套的循环，并基于外部循环在一个循环内选择

我有以下阵列：

$payments = array(1=>'Cash',2=>Cheque,3=>credit,4=>other);
$selected = array(2,1);

foreach($payments as $key=>$value) {
   foreach($selected as $id) {
      if ($key == $id) {
         echo $id . "is selected" . '<br>';
      }
      else{
          echo $id . " is not selected" . '<br>';
      }
   }
}

 what expected:
 1 is selected
 2 is not selected
 3 is not selected
 4 is selected

 but i got:
 1 is not selected
 1 is selected
 2 is selected
 2 is not selected
 3 is not selected
 3 is not selected
 4 is not selected
 4 is not selected

---

我的循环有什么问题？

您不需要内部循环：

$payments = array(1=>'Cash',2=>Cheque,3=>credit,4=>other);
$selected = array(2,1);

foreach($payments as $key=>$value) {
  if (in_array($key, $selected)( {
     echo $key . "is selected" . '<br>';
  } else {
      echo $key . " is not selected" . '<br>';
  }
}

foreach($payments as $key=>$value) {  
  if (in_array($key, $selected)) {
     echo $id . "is selected" . '<br>';
  }else{
      echo $id . " is not selected" . '<br>';
  }
}  

您可以简单地使用来检查是否选择了元素：

$payments = array(1=>'Cash',2=>'Cheque',3=>'credit',4=>'other');
$selected = array(2,1);

foreach($payments as $key=>$value) {
   if (in_array($key, $selected)) {
      echo $value . "is selected" . '<br>';
   } else {
      echo $value . " is not selected" . '<br>';
   }
}

顺便说一下，您需要在付款方式名称周围加引号。

您可以使用引号，这样您就可以省略内部循环：

$payments = array(1=>'Cash',2=>Cheque,3=>credit,4=>other);
$selected = array(2,1);

foreach($payments as $key=>$value) {
  if (in_array($key, $selected)( {
     echo $key . "is selected" . '<br>';
  } else {
      echo $key . " is not selected" . '<br>';
  }
}

foreach($payments as $key=>$value) {  
  if (in_array($key, $selected)) {
     echo $id . "is selected" . '<br>';
  }else{
      echo $id . " is not selected" . '<br>';
  }
}  

更新：一种替代解决方案。也许不是更好，但不同：

$payments = array(1=>'Cash', 2=>'Cheque', 3=>'Credit', 4=>'Other');
$selected = array('Cash','Cheque');

foreach($selected as $chosen){  
    $selected_values = array_search($chosen, $payments);
    echo "Number ". $selected_values." (".$chosen.") is selected.<br>";
} 

像其他人一样的老办法

    $payments = array(1=>'Cash', 2=>'Cheque',3=>'Credit',4=>'Other');

    $selected = array(2,1);

    foreach($payments as $key=>$value) {  
      if (in_array($key, $selected)) {
         echo $key. " is selected" . '<br>';
      }else{
          echo $key. " is not selected" . '<br>';
      }
    } 

---

哈哈，一分钟内有4个几乎相同的答案。顺便问一下，你为什么期待这些结果？它与您的$selected数组不一致，这意味着只选择了2和1。我认为OP没有得到预期的答案谢谢各位，下面的所有答案都是正确的。遗忘在数组中：然后请用期望的答案更新问题，并接受其中一个答案。OP：请让我知道这是否是您想要的，或者我是否可以在数组中以任何其他方式帮助您。祝您有个美好的一天。