php - 如何合并两个数组，但在日期常见的地方合并它们

Question

我有两个数组，我想合并它们，但合并日期相同的地方。我设法合并它们，但如果日期相同，它将它们合并为不同的条目。这是我的 2 个数组:arr1:

[{"y":"2015-03-05","item1":"850","item2":"0"},
{"y":"2015-03-19","item1":"8377","item2":"0"},
{"y":"2015-05-27","item1":"1037","item2":"0"},
{"y":"2015-10-15","item1":"5402","item2":"0"}]

arr2:

[{"y":"2015-04-29","item1":"0","item2":"1008"},
{"y":"2015-05-27","item1":"0","item2":"25"}]

当我使用 $arr = array_merge($arr1, $arr2); 时，它会合并它们，但日期很常见，在我的情况下 2015-05-27 我想将它们合并到 "y":"2015-05-27","item1":"1037","item2":"25"

Answer 1

您可以尝试这种方法，将日期的项目数组映射到具有 date 键的关联数组，然后仅添加具有非零值的其他项目。请参阅代码中的注释:

// Make PHP arrays of JSON
$items1 = json_decode('[
{"y":"2015-03-05","item1":"850","item2":"0"},
{"y":"2015-03-19","item1":"8377","item2":"0"},
{"y":"2015-05-27","item1":"1037","item2":"0"},
{"y":"2015-10-15","item1":"5402","item2":"0"}]', true);

$items2 = json_decode('[
{"y":"2015-04-29","item1":"0","item2":"1008"},
{"y":"2015-05-27","item1":"0","item2":"25"}]', true);

// Define an associative array like:
// [
//   '<date>' => [ 'item1' => '<n>', 'item2' => "<n>" ],
//   ...
// ]
$itemsPerDay = [];

// Loop arrays
foreach (array_merge($items1, $items2) as $array) {
    $date = $array['y']; // Get date

    if (!isset($itemsPerDay[$date])) {
        // If array for date not set in associative array, use full array
        $itemsPerDay[$date] = $array;
    }
    else {
        // If array for date already exists, merge only items having a
        // non-empty value
        $nonEmptyValues = array_filter($array, function($w) { return !empty($w); });
        $itemsPerDay[$date] = array_merge($itemsPerDay[$date], $nonEmptyValues);
    }
}

// Get values part of associative array
$itemsPerDay = array_values($itemsPerDay);

// Output JSON
echo json_encode($itemsPerDay);

输出(为了清晰起见，缩进):

[{"y": "2015-03-05", "item1": "850",  "item2": "0"},
 {"y": "2015-03-19", "item1": "8377", "item2": "0"},
 {"y": "2015-05-27", "item1": "1037", "item2": "25"},
 {"y": "2015-10-15", "item1": "5402", "item2": "0"},
 {"y": "2015-04-29", "item1": "0",    "item2": "1008"}]