使用两个条件自定义排序数组

Question

我有以下数组：

$arr = [
    [
        'user_id' => 1,
        'product_id' => 1
    ],
    [
        'user_id' => 1,
        'product_id' => 2
    ],
    [
        'user_id' => 1,
        'product_id' => 3
    ],
    [
        'user_id' => 2,
        'product_id' => 1
    ],
    [
        'user_id' => 2,
        'product_id' => 2
    ],
    [
        'user_id' => 3,
        'product_id' => 1
    ]
];

我想对其进行排序，使其看起来像这样：

$arr = [
    [
        'user_id' => 1,
        'product_id' => 1
    ],
    [
        'user_id' => 2,
        'product_id' => 1
    ],
    [
        'user_id' => 3,
        'product_id' => 1
    ],
    [
        'user_id' => 1,
        'product_id' => 2
    ],
    [
        'user_id' => 2,
        'product_id' => 2
    ],
    [
        'user_id' => 1,
        'product_id' => 3
    ]
];

所以基本上我需要按product_id 和user_id 订购，以便在继续下一个用户之前从每个用户中选择较低的数字product_id。

我尝试使用usort，但无法使用。

usort($campaigns, function($a, $b){
    if($a['product_id'] == $b['product_id']){
        return 0;
    }

    if($a['product_id'] < $b['product_id']){

        if($a['user_id'] == $b['user_id']){
            return 1;
        }

        if($a['user_id'] < $a['user_id']){
            return 0;
        }

        return -1;
    }else{

        if($a['user_id'] == $a['user_id']){
            return -1;
        }

        if($a['user_id'] < $a['user_id']){
            return 0;
        }

        return 1;
    }
});

我也尝试了array_multisort，但我所能做的就是使用我已经从数据库中检索到的相同订单进行订购。

Answer 1

假设你的值是整数：

usort($campaigns, function($a, $b){
    if($a['product_id'] == $b['product_id']){
        return $a['user_id'] - $b['user_id'];
    } else {
        return $a['product_id'] - $b['product_id'];
    }
});

---

您还可以使用带有ORDER BY product_id, user_id 子句的数据库排序。

Answer 2

使用array_multisort 函数和“列数组”（很少排序维度）的解决方案：

$userIds = $productIds = [];
foreach ($arr as $k => $v) {
    $userIds[$k] = $v['user_id'];
    $productIds[$k] = $v['product_id'];
}

array_multisort($productIds, SORT_ASC, $userIds, SORT_ASC, $arr);

print_r($arr);

输出：

Array
(
    [0] => Array
        (
            [user_id] => 1
            [product_id] => 1
        )

    [1] => Array
        (
            [user_id] => 2
            [product_id] => 1
        )

    [2] => Array
        (
            [user_id] => 3
            [product_id] => 1
        )

    [3] => Array
        (
            [user_id] => 1
            [product_id] => 2
        )

    [4] => Array
        (
            [user_id] => 2
            [product_id] => 2
        )

    [5] => Array
        (
            [user_id] => 1
            [product_id] => 3
        )

)

Answer 3

$arrTags = [
    [
        'user_id' => 1,
        'product_id' => 1
    ],
    [
        'user_id' => 1,
        'product_id' => 2
    ],
    [
        'user_id' => 1,
        'product_id' => 3
    ],
    [
        'user_id' => 2,
        'product_id' => 1
    ],
    [
        'user_id' => 2,
        'product_id' => 2
    ],
    [
        'user_id' => 3,
        'product_id' => 1
    ]
];

foreach($arrTags as $key => $row){ 
$userArray[$key]  = $row['user_id'];
$productArray[$key] = $row['product_id'];
}

array_multisort($productArray, SORT_ASC, $userArray, SORT_ASC, $arrTags);
print_r($arrTags);

输出

 Array
(
    [0] => Array
        (
            [user_id] => 1
            [product_id] => 1
        )

    [1] => Array
        (
            [user_id] => 2
            [product_id] => 1
        )

    [2] => Array
        (
            [user_id] => 3
            [product_id] => 1
        )

    [3] => Array
        (
            [user_id] => 1
            [product_id] => 2
        )

    [4] => Array
        (
            [user_id] => 2
            [product_id] => 2
        )

    [5] => Array
        (
            [user_id] => 1
            [product_id] => 3
        )

)

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