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Example of specifying multi-field sorting for PHP multidimensional arrays
Example of specifying multi-field sorting for PHP multidimensional arrays
This article mainly introduces examples of specifying multi-field sorting for PHP multi-dimensional arrays. It has a certain reference value. Now I share it with you. Friends in need can refer to it.
Introducing the array_multisort method
array_multisort — Sort multiple arrays or multidimensional arrays. The instructions in the PHP manual are as follows:
Copy code The code is as follows:
bool array_multisort ( array &$arr [, mixed $arg = SORT_ASC [, mixed $arg = SORT_REGULAR [, mixed $... ]]] )
Parameters
arr
An array to be sorted.
#arg
Each of the following parameters can be another array or a sorting flag option parameter for the previous array: SORT_ASC, SORT_DESC, SORT_REGULAR, SORT_NUMERIC, SORT_STRING.
…
Additional arg's.
First implement the sorting of one field of the specified multi-dimensional array
Here it is required to sort the array according to one of the fields. The array assumptions are as follows:
$array = array(
0=>array('id'=>8,'name'=>'Tom'),
1=>array('id'=>9,'name'=>'Peter'),
2=>array('id'=>5,'name'=>'Jack')
);We need to sort according to the id value of the two-dimensional array. The converted array format is as follows:
$array = array(
0=>array('id'=>5,'name'=>'Jack')
1=>array('id'=>8,'name'=>'Tom'),
2=>array('id'=>9,'name'=>'Peter')
);To complete the above conversion, you need to use the array_multisort function introduced above, as follows:
function sortArrByOneField(&$array, $field, $desc = false){
$fieldArr = array();
foreach ($array as $k => $v) {
$fieldArr[$k] = $v[$field];
}
$sort = $desc == false ? SORT_ASC : SORT_DESC;
array_multisort($fieldArr, $sort, $array);
}By The $field of each array in the sorted array is stored in a one-bit array fieldArr and participates in sorting in the incoming array_multisort. The value of the field array is as follows:
array(0=>8,1=>9,2=>5)
After passing in array_multisort, it is equivalent to sorting the $field one-dimensional array, and then rebuilding it based on the sorted key The incoming array to be sorted.
Implementing sorting of multi-dimensional arrays by specifying multiple fields
The above example explains how to implement sorting of multi-dimensional arrays by specifying one field, but if you want How to think about specifying multiple fields to sort an array?
How many fields are there? 2, 3 or more, so this uncertain factor needs to be eliminated.
Let’s first look at the 2 solutions for specifying 2 fields for sorting:
$arr = array(
'0' => array(
'id' => 3,
'age' => 27
),
'1' => array(
'id' => 5,
'age' => 50
)，
'2' => array(
'id' => 4,
'age' => 44
),
'3' => array(
'id' => 3,
'age' => 78
)
);
foreach ( $arr as $key => $row ){
$id[$key] = $row ['id'];
$age[$key] = $row ['age'];
}
array_multisort($id, SORT_ASC, $age, SORT_DESC, $arr);
print_r($arr);
//result:Array([0]=>Array(['id']=>3 ['age']=>78) [1]=>Array(['id']=>3 ['age']=>27) [2]=>Array(['id']=>4 ['age']=>44) [3]=>Array(['id']=>5 ['age']=>50))Refactor the above code, just use php The func_get_args function in can dynamically obtain the incoming value, which can solve the problem of uncertain number of multiple fields. The implementation is as follows:
$array1 = array(
0=>array('id'=>8,'name'=>'Apple','age'=> 18),
1=>array('id'=>8,'name'=>'Bed','age'=>17),
2=>array('id'=>5,'name'=>'Cos','age'=>16),
3=>array('id'=>5,'name'=>'Cos','age'=>14)
);
function sortArrByManyField(){
$args = func_get_args();
if(empty($args)){
return null;
}
$arr = array_shift($args);
if(!is_array($arr)){
throw new Exception("第一个参数不为数组");
}
foreach($args as $key => $field){
if(is_string($field)){
$temp = array();
foreach($arr as $index=> $val){
$temp[$index] = $val[$field];
}
$args[$key] = $temp;
}
}
$args[] = &$arr;//引用值
call_user_func_array('array_multisort',$args);
return array_pop($args);
}
$arr = sortArrByManyField($array1,'id',SORT_ASC,'name',SORT_ASC,'age',SORT_DESC);
print_r($arr);The running result is as follows:
array(4) {
[0]=>array(3) {
["id"]=>int(5)
["name"]=>string(3) "Cos"
["age"]=>int(16)
}
[1]=>array(3) {
["id"]=>int(5)
["name"]=>string(3) "Cos"
["age"]=>int(14)
}
[2]=>array(3) {
["id"]=>int(8)
["name"]=>string(5) "Apple"
["age"]=>int(18)
}
[3]=>array(3) {
["id"]=>int(8)
["name"]=>string(3) "Bed"
["age"]=>int(17)
}
}The above is the entire content of this article, thank you for reading. Please pay attention to the PHP Chinese website for more information!
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