如何在php中以这种方式对数组进行排序

Question

like the function usort in php but if two members compare as equal, their key should be same. for example: $arrayToSort = array(2,6,1,3,3);

after sort return

array
  1 =>  1
  2 =>  2
  3 =>  3
  3 =>  3
  4 =>  6

Answer 1

Not sure if there's a native function but this might be what you want.

<?php
$arr = array(1,2,2,2,3);

function arrayKeyJoin( $arr ) {
    $newArr = array();
    foreach ( $arr as $item ) {
 if ( !in_array( $item, array_keys($newArr) ) ) {
     $newArr[$item] = array();
 }
 array_push( $newArr[$item], $item );
    }
    return $newArr;
}

echo '<pre>', var_dump( arrayKeyJoin( $arr ) ), '</pre>';

Output:

array(3) {
  [1]=>
  array(1) {
    [0]=>
    int(1)
  }
  [2]=>
  array(3) {
    [0]=>
    int(2)
    [1]=>
    int(2)
    [2]=>
    int(2)
  }
  [3]=>
  array(1) {
    [0]=>
    int(3)
  }
}