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HomeBackend DevelopmentPHP Tutorialphp array_map array_multisort efficiently handles multi-dimensional array sorting

To sort multi-dimensional arrays, the general approach is
1 to obtain the sorted data and put it into the array $arrSort. The key index is the index of the array to be sorted to ensure uniqueness
2 Use the sort function Sort and so on sort $arrSort.
3 Traverse $arrSort, obtain the data of the multi-dimensional array according to its index, and reconstruct the sorted multi-dimensional array.

Array 
( 
[0] => Array 
( 
[link] => test 
[name] => test.rpm 
[type] => file 
[size] => 988.9k 
[mtime] => 1185160178) 
.... 
)

I A sorting I found on the Internet a long time ago Function, not to say efficient, but very practical

_array_sort($arrFile, 1, 1);//根据name字段排序 
_array_sort($arrFile, 3, 1);//根据size字段排序 
/* 
@records 要排序的数组 
@field要排序的字段,注意是数字 
@reverse正序还是反序 
*/ 
function _array_sort($records, $field, $reverse, $defaultSortField = 0) 
{ 
$uniqueSortId = 0; 
$hash = array(); 
$sortedRecords = array(); 
$tempArr = array(); 
$indexedArray = array(); 
$recordArray = array(); 

foreach($records as $record) 
{ 
$uniqueSortId++; 
$recordStr = implode("|", $record)."|".$uniqueSortId; 
$recordArray[] = explode("|", $recordStr); 
} 

$primarySortIndex = count($record); 
$records = $recordArray; 

foreach($records as $record) 
{ 
$hash[$record[$primarySortIndex]] = $record[$field]; 
} 
uasort($hash, "strnatcasecmp"); 
if($reverse) 
$hash = array_reverse($hash, true); 

$valueCount = array_count_values($hash); 

foreach($hash as $primaryKey => $value) 
{ 
$indexedArray[] = $primaryKey; 
} 

$i = 0; 
foreach($hash as $primaryKey => $value) 
{ 
$i++; 
if($valueCount[$value] > 1) 
{ 
foreach($records as $record) 
{ 
if($primaryKey == $record[$primarySortIndex]) 
{ 
$tempArr[$record[$defaultSortField]."__".$i] = $record; 
break; 
} 
} 

$index = array_search($primaryKey, $indexedArray); 

if(($i == count($records)) || ($value != $hash[$indexedArray[$index+1]])) 
{ 
uksort($tempArr, "strnatcasecmp"); 

if($reverse) 
$tempArr = array_reverse($tempArr); 

foreach($tempArr as $newRecs) 
{ 
$sortedRecords [] = $newRecs; 
} 

$tempArr = array(); 
} 
} 
else 
{ 
foreach($records as $record) 
{ 
if($primaryKey == $record[$primarySortIndex]) 
{ 
$sortedRecords[] = $record; 
break; 
} 
} 
} 
} 
return $sortedRecords; 
}
II Use array_map and array_mutisort to sort

array_mutisor can also perform secondary or tertiary sorting based on multiple values, which is incomparable to the previous function .

利用array_map获取要依据排序的数组 
$arrField = array_map(create_function('$n', 'return $n["size"];'), $arrFile); 
//利用array_mutisort来进行排序 
$array_multisort($arrField, SORT_DESC, $arrFile);

III Final test
Test with an array of 188 data, sort 50 times to find the average.
The first method
0.04269016 name
0.04267142 size
The second method
0.001249 name
0.00083924 size

The results are self-evident

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