我需要一个按优先级排序项目数组的方法。
这是我到目前为止所做的工作：
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($values) . PHP_EOL;
}
}
预期：
A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
Foo
Foo
Bar
Bar
no type should be last
no type should be last
实际：
A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
no type should be last <-- should be at bottom
no type should be last <-- should be at bottom
Bar
Bar
Foo
Foo
问题是，没有给出$offset的项目应该总是排在最底层。
这意味着no type should be last应该总是低于Foo或Bar。
我怎样才能做到这一点？
<?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($array);
OUTPUT
Array
(
[21] => Array
(
[type] => A
)
[8] => Array
(
[type] => A
)
[18] => Array
(
[type] => B
)
[20] => Array
(
[type] => B
)
[6] => Array
(
[type] => C
)
[16] => Array
(
[type] => C
)
[11] => Array
(
[type] => D
)
[1] => Array
(
[type] => D
)
[7] => Array
(
[type] => E
)
[17] => Array
(
[type] => E
)
[13] => Array
(
[type] => F
)
[5] => Array
(
[type] => F
)
[15] => Array
(
[type] => G
)
[9] => Array
(
[type] => G
)
[4] => Array
(
[type] => H
)
[0] => Array
(
[type] => H
)
[19] => Array
(
[type] => Bar
)
[10] => Array
(
[type] => Foo
)
[14] => Array
(
[type] => Bar
)
[12] => Array
(
[type] => Foo
)
[2] => Array
(
[0] => no type should be last
)
[3] => Array
(
[0] => no type should be last
)
)
我决定使用@ vivek_23（编辑|固定）解决方案。
我编辑了不必要的else，如果f.e.将返回值更改为零。两个偏移都没有设定。
如果a和b缺少偏移或没有优先级，则函数应返回零imo。
工作代码：
uasort($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，浮点优先级，并且我不覆盖优先级（请参阅-99999999 @Eddie解决方案）。
经测试
// 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
$priorities = [
'A' => -6.5,
'B' => -7,
'C' => -6,
'D' => -5,
'E' => -4,
'F' => -3,
'G' => -2,
'H' => -1,
];
谢谢@ vivek_23 :)
您没有处理两个优先级相同的情况。
只需在三元组之前将以下内容添加到您的函数中：
if ($aPriority == $bPriority)
return 0;
所以看起来应该是这样的：
uasort($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 > $bPriority ? -1 : 1;
});
否则，您只是假设$ aPriority小于$ bPriority，如果它不是更大但它可以相等。
如果没有额外的if情况，另一种实现它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;
然后返回减法：
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;
});