php二维数组排序

场景：数据来自于excel，读取出来是二维数组，需要按照指定字段排序，类似于sql的order by功能，代码如下：

```
class demo {
public function test() {
$arr = array(
array(
'power' => 380,
'day' => 1,
'where' => 1,
),
array(
'power' => 380,
'day' => 2,
'where' => 1,
),
array(
'power' => 400,
'day' => 1,
'where' => 1,
),
array(
'power' => 380,
'day' => 3,
'where' => 1,
),
array(
'power' => 400,
'day' => 2,
'where' => 1,
),
array(
'power' => 380,
'day' => 8,
'where' => 1,
),
array(
'power' => 380,
'day' => 8,
'where' => 2,
),
array(
'power' => 500,
'day' => 1,
'where' => 1,
),
array(
'power' => 380,
'day' => 11,
'where' => 1,
),
array(
'power' => 380,
'day' => 5,
'where' => 1,
),
);

$orderArr = array(
'power' => 'asc',
'day' => 'asc',
'where' => 'asc',
);

// 调用排序函数
$this->sortBySelf($arr, $orderArr);

var_dump($arr);die;
}

/**
* 自定义排序.
*
* @param array $arr   要排序的数组.
* @param array $order 排序规则.
*
* @return array.
*/
private function sortBySelf(&$arr = array(), $order = array()) {
if (empty($order)) {
return $arr;
}

$sortFuncNameArr = array(
'desc' => 'descSortByKey',
'asc' => 'ascSortByKey',
);

$index = array();

$i = 0;
$keys = array_keys($order);
foreach ($order as $key => $value) {
if ($i == 0) {
$funcName = $sortFuncNameArr[$value];
usort($arr, self::$funcName($key));
// 定义第一个字段排序完的index
$index = $this->setIndex($arr, array_slice($keys,0,$i+1));
$i++;
continue;
}

if (empty($index)) {
break;
}

foreach ($index as $beSortKey => $range) {
if (count($range) <= 1) {
continue;
}

$tmpSortArr = array_slice($arr, $range[0], count($range), true);

$funcName = $sortFuncNameArr[$value];
usort($tmpSortArr, self::$funcName($key));

array_splice($arr, $range[0], count($range), $tmpSortArr);

// 定义index
$index = $this->setIndex($arr, array_slice($keys,0,$i+1));
}

$i++;
}

}

/**
* 每次排序完设置分区.
*
* @param array $arr       要排序的数组.
* @param array $beSortKey 已经排序完的字段.
*
* @return array.
*/
private function setIndex($arr = array(), $beSortKey = array()) {
$index = array();

foreach ($arr as $arrKey => $value) {
$real = '';
for ($i = 0; $i < count($beSortKey); $i++) {
$real .= $value[$beSortKey[$i]];
}
$index[$real][] = $arrKey;
}

return $index;
}

/**
* 倒序回调函数.
*
* @param string $key 要排序的KEY.
*
* @return Closure.
*/
public static function descSortByKey($key = '') {
return function ($a, $b) use ($key) {
if ($a[$key] == $b[$key])
return 0;
return ($a[$key] > $b[$key]) ? -1 : 1;
};
}

/**
* 正序回调函数.
*
* @param string $key 要排序的KEY.
*
* @return Closure.
*/
public static function ascSortByKey($key = '') {
return function ($a, $b) use ($key) {
if ($a[$key] == $b[$key])
return 0;
return ($a[$key] < $b[$key]) ? -1 : 1;
};
}

}
```