PHP 按优先级排序数组

Question

我需要一种按优先级对项目数组进行排序的方法。

这是我目前所做的工作：

function arraySortPriority(array &$array, $offset, array $priorities)
{
    uasort($array, function ($a, $b) use ($offset, $priorities) {
        if (!isset($a[$offset])) {
            $a[$offset] = null;
        }
        if (!isset($b[$offset])) {
            $b[$offset] = null;
        }
        if ($a[$offset] == $b[$offset]) {
            return 0;
        }
        $aPriority = isset($priorities[$a[$offset]])
            ? $priorities[$a[$offset]]
            : null;
        $bPriority = isset($priorities[$b[$offset]])
            ? $priorities[$b[$offset]]
            : null;
        return $aPriority > $bPriority ? -1 : 1;
    });
}

// an array to sort
$array = [
    ['type' => 'A'],
    ['type' => 'A'],
    ['type' => 'B'],
    ['type' => 'B'],
    ['type' => 'C'],
    ['type' => 'C'],
    ['type' => 'D'],
    ['type' => 'D'],
    ['type' => 'E'],
    ['type' => 'E'],
    ['type' => 'F'],
    ['type' => 'F'],
    ['type' => 'G'],
    ['type' => 'G'],
    ['type' => 'H'],
    ['type' => 'H'],
    ['type' => 'Foo'],
    ['type' => 'Foo'],
    ['type' => 'Bar'],
    ['type' => 'Bar'],
    [0 => 'no type should be last'],
    [0 => 'no type should be last'],
];
// shuffle the array
shuffle($array);
// set priorities
$priorities = [
    'A' => 8,
    'B' => 7,
    'C' => 6,
    'D' => 5,
    'E' => 4,
    'F' => 3,
    'G' => 2,
    'H' => 1,
];
// call
arraySortPriority($array, 'type', $priorities);
// test output
foreach ($array as $item) {
    if (isset($item['type'])) {
        echo "{$item['type']}\r\n";
    } else {
        $values = array_values($item);
        echo reset($values) . PHP_EOL;
    }
}

预期：

A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
Foo
Foo
Bar
Bar
no type should be last
no type should be last

实际：

A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
no type should be last   <-- should be at bottom
no type should be last   <-- should be at bottom
Bar
Bar
Foo
Foo

问题是没有给予 $offset 的项目应该总是排在底部。

这意味着 no type should be last 的排序应始终低于 Foo 或 Bar。

我该怎么做？

Answer 1

您没有处理两个优先级相同的情况。

解决方案 1

只需将以下内容添加到您的函数中的三元前：

if ($aPriority == $bPriority)
    return 0;

所以它应该是这样的：

uasort($array, function ($a, $b) use ($offset, $priorities) {
    if (!isset($a[$offset])) {
        $a[$offset] = null;
    }
    if (!isset($b[$offset])) {
        $b[$offset] = null;
    }
    if ($a[$offset] == $b[$offset]) {
        return 0;
    }

    $aPriority = isset($priorities[$a[$offset]])
        ? $priorities[$a[$offset]]
        : null;
    $bPriority = isset($priorities[$b[$offset]])
        ? $priorities[$b[$offset]]
        : null;

    if ($aPriority == $bPriority)
        return 0;

    return $aPriority > $bPriority ? -1 : 1;
});

否则，您只需假定 $aPriority 小于 $bPriority（如果它不大于但可以相等）。

解决方案 2

另一种无需额外 if 情况的方法是将优先级设置为 0 而不是 null 如果未设置：

$aPriority = isset($priorities[$a[$offset]])
    ? $priorities[$a[$offset]]
    : 0;
$bPriority = isset($priorities[$b[$offset]])
    ? $priorities[$b[$offset]]
    : 0;

然后return减法：

return $bPriority - $aPriority;

所以它看起来像这样：

uasort($array, function ($a, $b) use ($offset, $priorities) {
    if (!isset($a[$offset])) {
        $a[$offset] = null;
    }
    if (!isset($b[$offset])) {
        $b[$offset] = null;
    }
    if ($a[$offset] == $b[$offset]) {
        return 0;
    }

    $aPriority = isset($priorities[$a[$offset]])
        ? $priorities[$a[$offset]]
        : 0;
    $bPriority = isset($priorities[$b[$offset]])
        ? $priorities[$b[$offset]]
        : 0;

    return $bPriority - $aPriority;
});

Answer 2

<?php 

// an array to sort
$array = [
    ['type' => 'A'],
    ['type' => 'A'],
    ['type' => 'B'],
    ['type' => 'B'],
    ['type' => 'C'],
    ['type' => 'C'],
    ['type' => 'D'],
    ['type' => 'D'],
    ['type' => 'E'],
    ['type' => 'E'],
    ['type' => 'F'],
    ['type' => 'F'],
    ['type' => 'G'],
    ['type' => 'G'],
    ['type' => 'H'],
    ['type' => 'H'],
    ['type' => 'Foo'],
    ['type' => 'Foo'],
    ['type' => 'Bar'],
    ['type' => 'Bar'],
    [0 => 'no type should be last'],
    [0 => 'no type should be last'],
];
// shuffle the array
shuffle($array);
// set priorities
$priorities = [
    'A' => 8,
    'B' => 7,
    'C' => 6,
    'D' => 5,
    'E' => 4,
    'F' => 3,
    'G' => 2,
    'H' => 1,
];

uasort($array,function($a,$b) use ($priorities){
        if(!isset($a['type'])){
            if(!isset($b['type'])) return -1;
            return 1;
        }else if(!isset($b['type'])){
            return -1;
        }

        if(isset($priorities[$a['type']])){
            if(!isset($priorities[$b['type']])) return -1;

            if($priorities[$a['type']] > $priorities[$b['type']]) return -1;
            else if($priorities[$a['type']] < $priorities[$b['type']]) return 1;

        }else if(isset($priorities[$b['type']])){
            return 1;           
        }

        return 0;
});

echo "<pre>";
print_r($array);

输出

Array
(
    [21] => Array
        (
            [type] => A
        )

    [8] => Array
        (
            [type] => A
        )

    [18] => Array
        (
            [type] => B
        )

    [20] => Array
        (
            [type] => B
        )

    [6] => Array
        (
            [type] => C
        )

    [16] => Array
        (
            [type] => C
        )

    [11] => Array
        (
            [type] => D
        )

    [1] => Array
        (
            [type] => D
        )

    [7] => Array
        (
            [type] => E
        )

    [17] => Array
        (
            [type] => E
        )

    [13] => Array
        (
            [type] => F
        )

    [5] => Array
        (
            [type] => F
        )

    [15] => Array
        (
            [type] => G
        )

    [9] => Array
        (
            [type] => G
        )

    [4] => Array
        (
            [type] => H
        )

    [0] => Array
        (
            [type] => H
        )

    [19] => Array
        (
            [type] => Bar
        )

    [10] => Array
        (
            [type] => Foo
        )

    [14] => Array
        (
            [type] => Bar
        )

    [12] => Array
        (
            [type] => Foo
        )

    [2] => Array
        (
            [0] => no type should be last
        )

    [3] => Array
        (
            [0] => no type should be last
        )

)

Answer 3

我决定使用@vivek_23（已编辑|修复）解决方案。

我删除了不必要的 else 并将 return 值更改为零，如果 f.e。两个偏移量都未设置。

如果 a 和 b 缺少偏移量或没有优先级，则函数应该 return 零 imo。

工作代码：

uasort($array, function ($a, $b) use ($offset, $priorities) {
    if (!isset($a[$offset])) {
        return !isset($b[$offset])
            ? 0
            : 1; // down
    } elseif (!isset($b[$offset])) {
        return -1; // up
    }
    if (isset($priorities[$a[$offset]])) {
        if (!isset($priorities[$b[$offset]])) {
            return -1; // up
        }
        return $priorities[$a[$offset]] > $priorities[$b[$offset]]
            ? -1 // up
            : 1; // down
    }
    return isset($priorities[$b[$offset]])
        ? 1 // down
        : 0;
});

这允许我使用负优先级、浮动优先级并且我不覆盖优先级（参见 -99999999 @Eddie 解决方案）。

已测试

// expect A, A, B, B, C, C, ... "no type ..." at bottom
$priorities = [
    'A' => 8,
    'B' => 7,
    'C' => 6,
    'D' => 5,
    'E' => 4,
    'F' => 3,
    'G' => 2,
    'H' => 1,
];

// expect "no type ..." at bottom, ..., C, C, B, B, A, A
$priorities = [
    'A' => -8,
    'B' => -7,
    'C' => -6,
    'D' => -5,
    'E' => -4,
    'F' => -3,
    'G' => -2,
    'H' => -1,
];

// expect B, B, A, A, C, C, ... "no type ..." at bottom
$priorities = [
    'A' => 6.5,
    'B' => 7,
    'C' => 6,
    'D' => 5,
    'E' => 4,
    'F' => 3,
    'G' => 2,
    'H' => 1,
];

// expect "no type ..." at bottom, ..., C, C, A, A, B, B
$priorities = [
    'A' => -6.5,
    'B' => -7,
    'C' => -6,
    'D' => -5,
    'E' => -4,
    'F' => -3,
    'G' => -2,
    'H' => -1,
];

感谢@vivek_23 :)

Answer 4

您的排序有 3 个逻辑规则。宇宙飞船运算符提供了非常清晰简洁的语法，没有混乱的条件块。

只要在三向比较运算符(<=>)两边写上相应的元素，规则就会从左到右得到遵守。当 $b 是 first/top/left 数组时，则应用 DESC 顺序；反之，first/top/left数组中的$a等同于ASC排序。

按目标列 DESC 的存在进行排序
然后打破#1 关系，按优先级值 DESC
然后打破#2 关系，按目标列值 ASC 排序

代码：(Demo)

function arraySortPriority(array &$array, $column, array $priorities):void
{
    usort($array, function($a, $b) use ($column, $priorities) {
        $aFocus = $a[$column] ?? null;
        $bFocus = $b[$column] ?? null;
        return [array_key_exists($column, $b), $priorities[$bFocus] ?? 0, $aFocus]
               <=>
               [array_key_exists($column, $a), $priorities[$aFocus] ?? 0, $bFocus];
    });
}

arraySortPriority($array, 'type', $priorities);
var_export($array)

_{如果您的 $array 永远不会包含 null 值，则可以进一步优化此代码段以在 usort() 范围内不包含任何函数调用。}

PHP 按优先级排序数组

PHP sort array by priority

php

arrays

sorting

offset

解决方案 1

解决方案 2