php：如何按键更新关联数组中的值

我很难更新数组中的值。我举了一个简单的例子来说明这一点：数组包含玩家的名字和他们拥有的点数。在每一轮之后，我想像这样更新他们的分数：

（不起作用）

一定是什么蠢事，但我已经试了好几个小时了，就是找不到

谢谢你的帮助

您需要添加一个到

$player

：

$players = array (
  array (
   "id"        => 0,
   "name"      => "John",
   "points"    => 0
   ),

   array (
   "id"        => 1,
   "name"      => "Chris",
   "points"    => 0
   ),

   array (
   "id"        => 2,
   "name"      => "Peter",
   "points"    => 0
   ),

   array (
   "id"        => 3,
   "name"      => "Greg",
   "points"    => 0
   ),

);


$points0 = 10;
$points1 = 20;
$points2 = 30;
$points3 = 40;


$i = 0;
foreach ($players as &$player) {
  if ($player["id"] == $i) {
    $player["points"] = ${"points".$i};
  }
  $i++;
}

---

关键部分是

foreach

语句中的符号

&

。没有它，您就不会记录对阵列的任何更改。

似乎您希望使用循环来记录更改。如果是这种情况，您可能需要考虑将<代码> $Poxs/Cuff>变量更改为数组，如下面的代码演示：

<?php


    $players = array (
        array (
            "id"        => 0,
            "name"      => "John",
            "points"    => 0
        ),

        array (
            "id"        => 1,
            "name"      => "Chris",
            "points"    => 0
        ),

        array (
            "id"        => 2,
            "name"      => "Peter",
            "points"    => 0
        ),

        array (
            "id"        => 3,
            "name"      => "Greg",
            "points"    => 0
        ),

    );

    // IF YOU INTEND TO ASSIGN THE VALUES USING A LOOP, IT IS SUGGESTED TO
    // RATHER MAKE $points AN ARRAY WITH EACH KEY CORRESPONDING TO THE KEY OF THE
    // MULTIDIMENSIONAL ARRAY $players AND THE VALUE BEING THE POINT TO BE ASSIGNED
    // TO THE SUB-ARRAY WITH THAT KEY LIKE SO:
    $points = [
      0   => 10,//IMPLIES: TARGET $players[0] & ADD 10 TO ITS points ITEM: "John"
      1   => 20,//IMPLIES: TARGET $players[1] & ADD 20 TO ITS points ITEM: "Chris"
      2   => 30,//IMPLIES: TARGET $players[2] & ADD 30 TO ITS points ITEM: "Peter"
      3   => 40,//IMPLIES: TARGET $players[3] & ADD 40 TO ITS points ITEM: "Greg"
    ];

    // NOW LOOP THROUGH THE $players MULTIDIMENSIONAL ARRAY...
    // AS YOU ITERATE THROUGH IT, TRY TO OBTAIN THE POINTS FROM THE $points ARRAY
    // USING THE LOOP INDEX ($key)....
    // IT IS ALSO IMPORTANT TO WORK WITH EACH PLAYER BY REFERENCE
    // USING THE & OPERATOR
    foreach ($players as $key=>&$player) {  // NOTICE THE &$player here
        $currentPlayersPoints   = $points[$key];
        // HAVING OBTAINED THE CURRENT PLAYER'S POINTS,
        // SIMPLY ADD THE VALUE TO THE THE ORIGINAL points ELEMENT
        $player['points'] += (int)$currentPlayersPoints;
    }

    // CHECK OUT YOUR RESULT::
    var_dump($players);

    // YIELDS:  
    array (size=4)
      0 => 
        array (size=3)
          'id'      => int 0
          'name'    => string 'John' (length=4)
          'points'  => int 10
      1 => 
        array (size=3)
          'id'      => int 1
          'name'    => string 'Chris' (length=5)
          'points'  => int 20
      2 => 
        array (size=3)
          'id'      => int 2
          'name'    => string 'Peter' (length=5)
          'points'  => int 30
      3 => 
        array (size=3)
          'id'      => int 3
          'name'    => string 'Greg' (length=4)
          'points'  => int 40

---

您调试代码了吗？查看压缩和分配之间的差异
$player[“points”]==${“points”。$i}你在这里比较，你想分配我相信
$player[“points”]=${“points”。$I}-编辑：第一位；-）您可能希望对点使用数组<代码>$points[0]=10$点[1]=20等等。然后你可以做
foreach（$player作为$player）{$player['points']=$points[$player['id']]；}
@Fred ii-在这种情况下，
{}
意味着什么（变量）？那是不是叫了个名字好让我读一下？@AntonisTsimourtos variables-variable-dam。。。为什么呢？我不明白。谢谢@罗德赫
<?php


    $players = array (
        array (
            "id"        => 0,
            "name"      => "John",
            "points"    => 0
        ),

        array (
            "id"        => 1,
            "name"      => "Chris",
            "points"    => 0
        ),

        array (
            "id"        => 2,
            "name"      => "Peter",
            "points"    => 0
        ),

        array (
            "id"        => 3,
            "name"      => "Greg",
            "points"    => 0
        ),

    );

    // IF YOU INTEND TO ASSIGN THE VALUES USING A LOOP, IT IS SUGGESTED TO
    // RATHER MAKE $points AN ARRAY WITH EACH KEY CORRESPONDING TO THE KEY OF THE
    // MULTIDIMENSIONAL ARRAY $players AND THE VALUE BEING THE POINT TO BE ASSIGNED
    // TO THE SUB-ARRAY WITH THAT KEY LIKE SO:
    $points = [
      0   => 10,//IMPLIES: TARGET $players[0] & ADD 10 TO ITS points ITEM: "John"
      1   => 20,//IMPLIES: TARGET $players[1] & ADD 20 TO ITS points ITEM: "Chris"
      2   => 30,//IMPLIES: TARGET $players[2] & ADD 30 TO ITS points ITEM: "Peter"
      3   => 40,//IMPLIES: TARGET $players[3] & ADD 40 TO ITS points ITEM: "Greg"
    ];

    // NOW LOOP THROUGH THE $players MULTIDIMENSIONAL ARRAY...
    // AS YOU ITERATE THROUGH IT, TRY TO OBTAIN THE POINTS FROM THE $points ARRAY
    // USING THE LOOP INDEX ($key)....
    // IT IS ALSO IMPORTANT TO WORK WITH EACH PLAYER BY REFERENCE
    // USING THE & OPERATOR
    foreach ($players as $key=>&$player) {  // NOTICE THE &$player here
        $currentPlayersPoints   = $points[$key];
        // HAVING OBTAINED THE CURRENT PLAYER'S POINTS,
        // SIMPLY ADD THE VALUE TO THE THE ORIGINAL points ELEMENT
        $player['points'] += (int)$currentPlayersPoints;
    }

    // CHECK OUT YOUR RESULT::
    var_dump($players);

    // YIELDS:  
    array (size=4)
      0 => 
        array (size=3)
          'id'      => int 0
          'name'    => string 'John' (length=4)
          'points'  => int 10
      1 => 
        array (size=3)
          'id'      => int 1
          'name'    => string 'Chris' (length=5)
          'points'  => int 20
      2 => 
        array (size=3)
          'id'      => int 2
          'name'    => string 'Peter' (length=5)
          'points'  => int 30
      3 => 
        array (size=3)
          'id'      => int 3
          'name'    => string 'Greg' (length=4)
          'points'  => int 40