php二维数据某个字段值相同则放到一起,[宜配屋]听图阁

您可以使用 PHP 中的 array_reduce 函数来实现这个功能。具体步骤如下：

1. 创建一个空数组 $result 以存储结果。
2. 使用 foreach 循环遍历原始数组 $data。
3. 在循环中，检查是否已经存在一个数组键名为当前元素指定字段的值。如果存在，则将当前元素添加到该键名对应的子数组中；否则，在 $result 中创建一个新的子数组，并将当前元素添加到其中。
4. 返回 $result。

以下是示例代码：

function groupByField($data, $field) {
    $result = [];
    foreach ($data as $item) {
        $key = $item[$field];
        if (array_key_exists($key, $result)) {
            $result[$key][] = $item;
        } else {
            $result[$key] = [$item];
        }
    }
    return $result;
}

假设原始数组 $data 如下所示：

$data = [
    ["name" => "John", "age" => 20, "city" => "New York"],
    ["name" => "Alice", "age" => 25, "city" => "Los Angeles"],
    ["name" => "Bob", "age" => 30, "city" => "New York"],
    ["name" => "David", "age" => 35, "city" => "San Francisco"],
    ["name" => "Eve", "age" => 40, "city" => "New York"],
];

如果要按照城市将元素分组，可以调用 groupByField($data, "city")，将返回以下结果：

[
    "New York" => [
        ["name" => "John", "age" => 20, "city" => "New York"],
        ["name" => "Bob", "age" => 30, "city" => "New York"],
        ["name" => "Eve", "age" => 40, "city" => "New York"],
    ],
    "Los Angeles" => [
        ["name" => "Alice", "age" => 25, "city" => "Los Angeles"],
    ],
    "San Francisco" => [
        ["name" => "David", "age" => 35, "city" => "San Francisco"],
    ],
];