将元素推入缺少月份的数组

Question

我想用零填充数组中缺失的月份。

输入数据：

$d = [
        [
          'type' =>  25500,
          'month' => 'July'
         ],
         [
          'type' => 5465,
          'month' => 'January'
         ],
         [
          'type' => 40000,
          'month' => 'April'
         ],
         [
          'type' => 35000,
          'month' => 'June'
         ],
         [
          'type' => 10000,
          'month' => 'February'
     ]
 ];

$allmonths = ['January','February','March', 'April','May','June','July','August','September','October','November','December'];

我的代码：

$res = [];
foreach ($allmonths  as $key => $mes) {
    $teste = array_search($mes, array_column($d, 'month'));
    if ($teste) {
        $res[$teste] = ['type' => 2, 'moth '=> $mes];
    } else {
        $res[] = ['type' => 0,'moth '=> $mes];
    }
}

我一直在尝试解决这个问题，但没有成功。

预期结果：

Array
(
    [0] => Array
        (
            [type] => 25500
            [month] => July
        )
    [1] => Array
        (
            [type] => 5465
            [month] => January
        )
    [2] => Array
        (
            [type] => 40000
            [month] => April
        )
    [3] => Array
        (
            [type] => 35000
            [month] => June
        )
    [4] => Array
        (
            [type] => 10000
            [month] => February
        )
    [5] => Array
        (
            [type] => 0
            [month] => March
        )
    [6] => Array
        (
            [type] => 0
            [month] => May
        )
    [7] => Array
        (
            [type] => 0
            [month] => August
        )
    [8] => Array
        (
            [type] => 0
            [month] => September
        )
    [9] => Array
        (
            [type] => 0
            [month] => October
        )
    [10] => Array
        (
            [type] => 0
            [month] => November
        )
    [11] => Array
        (
            [type] => 0
            [month] => December
        )
)

Answer 1

类似这样的方法可行：

<?php

$d = [
       [
         'type' =>  25500,
         'month' => 'July'
        ],
        [
         'type' => 5465,
         'month' => 'January'
        ],
        [
         'type' => 40000,
         'month' => 'April'
        ],
        [
         'type' => 35000,
         'month' => 'June'
        ],
        [
         'type' => 10000,
         'month' => 'February'
        ]
      ];

$allmonths = ['January','February','March', 'April','May','June','July','August','September','October','November','December'];

$present_months = array_column($d, 'month');

foreach ($allmonths as $month) {
    if (!in_array($month, $present_months)) {
        $d[] = [
            'type' => 0,
            'month' => $month,
        ];
    }
}

var_dump($d);

Answer 2

由于这里的objective是将缺失的月份追加到原始数组$d而不改变现有的elements（按照预期结果），我们可以简单地改变$d 而不是创建新变量 $res.

同时转换数组的键 $d 将使它更容易使用。这确实假设 month 在 $d.

中只出现一次

Link to working example

## Assumption: Month is unique
$dNew = array_column($d, null, 'month');
$res = [];
foreach ($allmonths as $key => $mes) {
    if (!isset($dNew[$mes])) {
        $d[] = ['type' => 0, 'moth ' => $mes];
    }
}
var_dump($d);

如果 month 在数组中不是唯一的，您可以使用 array_search 或 in_array 来获得类似的结果。

$dNew = array_column($d,  'month');
$res = [];
foreach ($allmonths as $key => $mes) {
    if (!array_search($mes, $dNew)) {
        $d[] = ['type' => 0, 'moth ' => $mes];
    }
}
print_r($d);

Answer 3

我会选择 array_column(), array_diff() 和一个 foreach()

进程：

1)创建所有月份的数组

2)使用 array_column().

获取数组中的所有月份

3)使用 array_diff().

查找数组中不可用的月份

4)迭代这个差异并将它们添加到当前数组。

$allMonths = ['January','February','March', 'April','May','June','July','August','September','October','November','December'];

$currentMonths = array_column($d, 'month');

$notIncludedMonth = array_diff($allMonths,$currentMonths);

foreach ($notIncludedMonth as $month) {
    $d[] = [
        'type' => 0,
        'month' => $month,
    ];
}

print_r($d);

输出：https://3v4l.org/GsFoO

Answer 4

这个答案需要付出额外的努力来安排月份（不是你要求的——我只是觉得合适）。

此外，效率可能不是这项任务的重点，但为了研究人员的利益，我将表达 in_array()、array_search()、array_diff() 和任何其他“值比较”技术无法像 array_key_exists()、isset()、??（空合并运算符）、array_diff_key() 等“键比较”技术那样高效地工作。出于这个原因，我赞成努力的第一个片段——!isset() 将在一个循环中表现得很好。

这是我的替代方案，它不进行迭代函数调用（但会迭代整个月份数组）。 (Demo)

$lookup = array_column($d, null, 'month');  // assign temporary keys for improved efficiency

$result = [];
foreach ($allmonths as $month) {
    $result[] = $lookup[$month] ?? ['type' => 0, 'month' => $month];
}
var_export($result);

将元素推入缺少月份的数组

Push elements into array where a month is missing

php

arrays

default-value