Question

我试图循环这个数组，但我仍然得到错误

我有一个这样的数组：

1 => ["name"=>"A", "related"=>[
["signal"=>"A1", "color"=>"green"],
["signal"=>"A2", "color"=>"lime"],
["signal"=>"A3","color"=>"yellowGreen"]
]] 
2 => ["name"=>"B", "related"=>[
["signal"=>"B1", "color"=>"Red"],
["signal"=>"B2", "color"=>"Pink"]
]]

如何显示为 - A：绿色，石灰色，黄色格里布 - B：红色，粉红色

这是我尝试以上述格式显示的代码

foreach($arr as $key => $value){
  echo $value["name"];
  foreach($value["related"] as $k){
    echo $k["color"] . ",";
  }
}

抛出错误，这个数组没有$ value [＆＃34;相关＆＃34;]索引。但它可以回应$ value [＆＃34; name＆＃34;] ???

谢谢！

Answer 1

找到解决方案如下：

$array = [1 => [
    "name" => "A",
    "related" => [
        ["signal" => "A1", "color" => "green"],
        ["signal" => "A2", "color" => "lime"],
        ["signal" => "A3", "color" => "yellowGreen"]
    ]
],
    2 => ["name" => "B", "related" => [
        ["signal" => "B1", "color" => "Red"],
        ["signal" => "B2", "color" => "Pink"]
    ]]
];

foreach ($array as $ar) {
    $new_arr = array_column($ar['related'], 'color');
    $required_string = implode(', ', $new_arr);
    echo $ar['name'].' : ' .$required_string;
    echo "<br />";
}

对于PHP版本＆lt; 5.5你可以使用以下解决方案：

foreach ($array as $ar) {
    $new_arr = array_map(function ($value) {
        return  $value['color'];
    }, $ar['related']);
    $required_string = implode(', ', $new_arr);
    echo $ar['name'].' : ' .$required_string;
    echo "<br />";
}

您可以在http://php.net/manual/en/control-structures.foreach.php

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