foreach 在每次迭代 php 中附加额外的值？答案

【问题标题】：foreach appending extra values in each iteration php?foreach 在每次迭代 php 中附加额外的值？
【发布时间】：2022-06-10 17:05:40
【问题描述】：

我有一个数组，我想按具有特定 ID 的数组分组。例如 $newArr =

得到上面的数组，我想要这样的结果:(id 明智和该 id 内的所有城市明智):

Array
(
    [10000024] => Array
        (
            [id] => 10000024
            [cat_name] => category_1
            [field] => search_type
            [palanpur] => 0
            [pattukottai] => 0
            [puttur] => 0
        )

    [10000086] => Array
        (
            [id] => 10000086
            [cat_name] => category_2
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 2
            [puttur] => 2
        )

    [10000059] => Array
        (
            [id] => 10000059
            [cat_name] => category_3
            [field] => search_type
            [palanpur] => 0
            [pattukottai] => 0
            [puttur] => 0
            [universal] => 0
        )

    [10000060] => Array
        (
            [id] => 10000060
            [cat_name] => category_4
            [field] => search_type
            [palanpur] => 0
            [pattukottai] => 0
            [puttur] => 0
            [universal] => 0
        )

)

为此，我试图通过 $result 中的 id 获取数据，但没有得到正确的结果。第一个数组循环以获取我想要的新数组： $fields = //用户输入；

foreach($newArr as $k1 =>  $val2){ 
                    $newArray['id'] = $val2['id'];
                    $newArray['cat_name'] = $val2['cat_name'];
                    $newArray['field'] = $fields;
                    if (array_key_exists('city', $val2)){ 
                        $city1 = $val2['city'];
                    } 
                    else { 
                        $city1 = "universal";
                    }
                    $newArray[$city1] = $val2[$fields];
                    $newArray1[] =  $newArray;
                }

在 $newArray1 中，我得到了这样的附加数据：错误的输出：

Array
(
    [0] => Array
        (
            [id] => 10000024
            [cat_name] => category_1
            [field] => search_type
            [palanpur] => 0
        )

    [1] => Array
        (
            [id] => 10000086
            [cat_name] => category_2
            [field] => search_type
            [palanpur] => 2
        )

    [2] => Array
        (
            [id] => 10000024
            [cat_name] => category_1
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 0
        )

    [3] => Array
        (
            [id] => 10000086
            [cat_name] => category_2
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 2
        )

    [4] => Array
        (
            [id] => 10000024
            [cat_name] => category_1
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 2
            [puttur] => 0
        )

    [5] => Array
        (
            [id] => 10000086
            [cat_name] => category_2
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 2
            [puttur] => 2
        )

    [6] => Array
        (
            [id] => 10000059
            [cat_name] => category_3
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 2
            [puttur] => 2
            [universal] => 0
        )

    [7] => Array
        (
            [id] => 10000060
            [cat_name] => category_4
            [field] => search_type
            [palanpur] => 2
            [pattukottai] => 2
            [puttur] => 2
            [universal] => 0
        )

)

请帮助获得预期的输出。

【问题讨论】：

标签： php foreach

【解决方案1】：

你快到了，你只是在搞乱字符串/数字。

如果你想完全复制新数组中的旧值 => id，

只是

$newA = array();
foreach ($oldA as $k => $v) {
    $code = $v["id"]; 
    $newA["$code"] = $v;
}

您会得到一个结果数组，其中包含所有 ID 作为键，以及所有相同的值作为值。

无论如何，您在这些数组中使用了太多信息。您只需要 4 个值： id、city、cat 和搜索类型 id 将是一个键，因此在值中重复它是没有用的

所以，最好在复制时清理数组：

$newA = array();
foreach ($oldA as $k => $v) {
    // get the ID
    $id = $v["id"]; 

    // Remove the ID, because it will be the first level key of the new array. 
    // If you want you can remove this next line, to keep the ID between the values too
    unset($v["id"]);

    foreach ($v as $k1 => $v1) {

        // Remove all numeric keys, because those are duplicated infos
        if (is_int($k1)) continue;

        // Here it is. Set the array => $id => $k1 at value $v1
        // It means that, for example, $newA['10000055']['city'] = "palanpur"
        // Notice that you need to use commas, to convert id in string. 
        // As far as I know, You can't set the numeric value of the array at position 10000025... 
        // so you need to pass it as STRING! 
        $newA["$id"][$k1] = $v1; 
    }
}

这样你就得到了这些类型的数组：

array {
  [10000024]=>
    array(3) {
        ["city"]=> "palanpur"
        ["cat_name"]=> "cat"
        ["search_tipe"]=> 0
  }
}

只需要最少的信息，节省内存，让应用程序更快，更易于管理... ID 将是键，子键映射为旧数组。

【讨论】：

天哪，你的反应比我还快。非常优雅的解决方案！