php 二维数组如何对指定多个字段进行分组

方法1：

function group_by_multiple_keys($array, $keys)
{
	$result = [];
	foreach ($array as $item) {
		// 从第一个键开始
		$current_level = &$result;
		foreach ($keys as $key) {
			// 如果当前键不存在，则创建一个空数组
			if (!isset($current_level[$item[$key]])) {
				$current_level[$item[$key]] = [];
			}
			// 移动到下一个嵌套级别
			$current_level = &$current_level[$item[$key]];
		}
		// 到达最后一个键，将原始项添加到数组中
		$current_level[] = $item;
	}
	return $result;
}

方法2：

function group_by_multiple_keys($array, $keys)
{
	$result = [];
	foreach ($array as $item) {
		$groupKey = [];
		foreach ($keys as $key) {
			$groupKey[] = $item[$key];
		}
		$groupKey            = implode('-', $groupKey);
		$result[$groupKey][] = $item;
	}

	$grouped = [];
	foreach ($result as $key => $group) {
		$keys                        = explode('-', $key);
		$grouped[$keys[0]][$keys[1]] = $group;
	}
	return $grouped;
}

方法3：

function group_by_multiple_keys($array, $keys)
{
	$reduced = array_reduce($array, function ($carry, $item) use ($keys) {
		$carryKey = [];
		foreach ($keys as $key) {
			$carryKey[] = $item[$key];
		}
		$carryKey           = implode('-', $carryKey);
		$carry[$carryKey][] = $item;
		return $carry;
	}, []);

	uksort($reduced, function ($a, $b) use ($keys) {
		$aParts = explode('-', $a);
		$bParts = explode('-', $b);
		foreach ($keys as $index => $key) {
			if ($aParts[$index] === $bParts[$index]) continue;
			return $aParts[$index] <=> $bParts[$index];
		}
		return 0;
	});

	$grouped = [];
	foreach ($reduced as $key => $group) {
		$keys                        = explode('-', $key);
		$grouped[$keys[0]][$keys[1]] = $group;
	}
	return $grouped;
}