组合多维数组答案

【问题标题】：Combining Multidimensional Arrays组合多维数组
【发布时间】：2017-03-27 21:06:43
【问题描述】：

我有两个数组，我想根据三个值（group_id、user_id、unit_id）的匹配来组合。如果这些值出现在一个数组中而不出现在另一个数组中，我想插入一个字符串来指示不存在值。

数组 1：

Array
(
    [0] => Array
        (
            [group_id] => 1
            [user_id] => 7
            [unit_id] => 21382
            [amount] => 500
            [type] => A
        )

    [1] => Array
        (
            [group_id] => 1
            [user_id] => 7
            [unit_id] => 24255
            [amount] => 300
            [type] => A
        )

    [2] => Array
        (
            [group_id] => 1
            [user_id] => 4
            [unit_id] => 21382
            [amount] => 50
            [type] => A
        )

    [3] => Array
        (
            [group_id] => 1
            [user_id] => 4
            [unit_id] => 24255
            [amount] => 67
            [type] => A
        )
)

数组 2：

Array
(
    [0] => Array
        (
            [group_id] => 1
            [user_id] => 7
            [unit_id] => 21382
            [amount] => 100
            [type] => B
        )

    [1] => Array
        (
            [group_id] => 1
            [user_id] => 7
            [unit_id] => 24255
            [amount] => 82
            [type] => B
        )
)

期望的结果：

Array
(
    [0] => Array
        (
            [group_id] => 1
            [user_id] => 7
            [unit_id] => 21382
            [A] => 500
            [B] => 100
        )

    [1] => Array
        (
            [group_id] => 1
            [user_id] => 7
            [unit_id] => 24255
            [A] => 300
            [B] => 82
        )
    [2] => Array
        (
            [group_id] => 1
            [user_id] => 4
            [unit_id] => 21382
            [A] => 50
            [B] => undefined
        )

    [3] => Array
        (
            [group_id] => 1
            [user_id] => 4
            [unit_id] => 24255
            [A] => 67
            [B] => undefined
        )
)

使用 foreach 循环我设法获得了部分结果，但这并不能说明值出现在一个数组中而不是另一个数组中的情况。

foreach ($array_1 as &$arr1) {
    foreach ($array_2 as $arr2) {
        if ($arr1['group_id'] == $arr2['group_id'] && $arr1['user_id'] == $arr2['user_id'] && $arr1['unit_id'] == $arr2['unit_id']) {
            $newArr[] = array('group_id'=>$arr1['group_id'], 'user_id'=>$arr1['user_id'], 'unit_id'=>$arr1['unit_id'], 'group_id'=>$arr1['group_id'], 'A'=>$arr1['amount'], 'B'=>$arr2['amount']);
            break;
        }
    }
}

【问题讨论】：

标签： php arrays multidimensional-array associative-array

【解决方案1】：

我的尝试，您可以将其他数组添加到 array_merge 命令。或者轻松添加类型，也可以在源数组中混合类型。

    $arr1 = array(
        array(
            'group_id' => 1,
            'user_id' => 7,
            'unit_id' => 21382,
            'amount' => 500,
            'type' => 'A',
        ),
        array(
            'group_id' => 1,
            'user_id' => 7,
            'unit_id' => 24255,
            'amount' => 300,
            'type' => 'A',
        ),
        array(
            'group_id' => 1,
            'user_id' => 4,
            'unit_id' => 21382,
            'amount' => 50,
            'type' => 'A',
        ),
        array(
            'group_id' => 1,
            'user_id' => 4,
            'unit_id' => 24255,
            'amount' => 67,
            'type' => 'A',
        ),
    );

    $arr2 = array(
        array(
            'group_id' => 1,
            'user_id' => 7,
            'unit_id' => 21382,
            'amount' => 100,
            'type' => 'B',
        ),
        array(
            'group_id' => 1,
            'user_id' => 7,
            'unit_id' => 24255,
            'amount' => 82,
            'type' => 'B',
        ),
    );

    $arrMerged = array_merge($arr1, $arr2);
    $desired = array();

    foreach ($arrMerged as $key => $val) {
        $retKey = false;
        foreach($desired as $desKey => $desVal) {
            if($desVal['group_id'] == $val['group_id']
            && $desVal['user_id'] == $val['user_id']
            && $desVal['unit_id'] == $val['unit_id']
            ) {
                $retKey = $desKey;
                break;
            }
        }
        if($retKey === false) {
            $desired[] = array(
                'group_id' => $val['group_id'],
                'user_id' => $val['user_id'],
                'unit_id' => $val['unit_id'],
                'A' => ($val['type'] == 'A' ? $val['amount'] : 'undefined'),
                'B' => ($val['type'] == 'B' ? $val['amount'] : 'undefined'),
            );
        } else {
            $desired[$retKey][$val['type']] = $val['amount'];
        }
    }

    var_dump($desired);

【讨论】：

【解决方案2】：

嵌套循环导致 O(n2) 复杂度非常昂贵。

如果您通过合并键（下面的 sn-p 中的$uKey）对数组进行索引，则可以对线性 O(n) 复杂度进行相同操作。

/**
 * build index
 *
 * @var array $index cumulative index
 * @var array $array array to add to index
 * @var array $uKey array of unique key names
 * @var array $template array of 'undefined' elements
 * @var string $char key to hold 'amount' value from $array
 */
function index(&$index, $array, $uKey, $template, $char) {
    foreach($array as $a) {
        $key = json_encode(array_intersect_key($a, $uKey));
        $val = isset($index[$key]) ? $index[$key] : [];
        $index[$key] = array_merge($template, $val, [$char => $a['amount']]);
    }      
}

// init empty index
$index = [];

// define vector
$uKey = array_flip(['group_id', 'user_id', 'unit_id']);

// define template
$template = ['A' => 'undefined', 'B' => 'undefined'];

// add arrays to index
index($index, $array1, $uKey, $template, 'A');
index($index, $array2, $uKey, $template, 'B');

// format index to reqquested output
$result = [];
foreach($index as $key=>$val) {
    $result[] = array_merge(json_decode($key, true), $val);
}
print_r($result)

【讨论】：

【解决方案3】：

假设 array1 将始终具有类型 A，而 array2 将具有类型 B 值/数量，下面的代码将给出所需的输出。

$array1 = array(
'0' => array('group_id' => 1,'user_id' => 7,'unit_id' => 21382, 'amount' => 500,'type' => 'A'),
'1' => array ('group_id' => 1, 'user_id' => 7,'unit_id' => 24255,'amount' => 300,'type' => 'A'),
'2' => array( 'group_id' => 1, 'user_id' => 4, 'unit_id' => 21382, 'amount' => 50,'type' => 'A' ),
'3' => array('group_id' => 1,'user_id' => 4,'unit_id' => 24255, 'amount' => 67, 'type' => 'A')
);

$array2 = array(
    '0' => array('group_id' => 1,'user_id' => 7,'unit_id' => 21382,'amount' => 100,'type' => 'B', ),
    '1' => array('group_id' => 1,'user_id' => 7,'unit_id' => 24255,'amount' => 82,'type' => 'B',)
);
// define an array
$new_array = array();
// loop first array
foreach($array1 as $key=>$value){
    // generate unique key
    $unique_key = $value['group_id'].'_'.$value['user_id'].'_'.$value['unit_id'];
    // loop the second array
    foreach($array2 as $k=>$v){
        // check the condition
        if ($value['group_id'] == $v['group_id'] && $value['user_id'] == $v['user_id'] && $value['unit_id'] == $v['unit_id']) {
           // generate array
           $new_array[$unique_key]=array('group_id'=>$value['group_id'],
           'user_id'=>$value['user_id'],
           'unit_id'=>$value['unit_id'],
           $value['type']=>$value['amount'],
           $v['type'] => $v['amount']
           ) ; 
        }else{
            $new_array[$unique_key]=array(
                'group_id'=>$value['group_id'],
           'user_id'=>$value['user_id'],
           'unit_id'=>$value['unit_id'],
           $value['type']=>$value['amount'],
           $v['type'] => 'Undefined'
           ) ;  
        }  
    }  
}
// returns indexed array with values 
$final_array = array_values($new_array);
print_r($final_array);

输出：

Array
(
[0] => Array
    (
        [group_id] => 1
        [user_id] => 7
        [unit_id] => 21382
        [A] => 500
        [B] => 100
    )

[1] => Array
    (
        [group_id] => 1
        [user_id] => 7
        [unit_id] => 24255
        [A] => 300
        [B] => 82
    )

[2] => Array
    (
        [group_id] => 1
        [user_id] => 4
        [unit_id] => 21382
        [A] => 50
        [B] => Undefined
    )

[3] => Array
    (
        [group_id] => 1
        [user_id] => 4
        [unit_id] => 24255
        [A] => 67
        [B] => Undefined
    )

)

【讨论】：