从2D数组中删除重复Id值：PHP

Question

I have an array like

$a = array(
    array('id'=>1, 'value'=>2),
    array('id'=>2, 'value'=>3),
    array('id'=>3, 'value'=>4),
    array('id'=>1, 'value'=>5),
    array('id'=>5, 'value'=>10),
    array('id'=>2, 'value'=>6),

);

from this i want an array which don't have the repeating id wise keys value e.g

$a = array(
    array('id'=>3, 'value'=>4),
    array('id'=>1, 'value'=>5),
    array('id'=>5, 'value'=>10),
    array('id'=>2, 'value'=>6)
);

i tried the following one but unable to get final result.

$i=0;
    foreach ($a as $key=>$value) {
        // $arr[$i] = $value;
        foreach ($a as $key1=>$value1) {
            if(!empty(array_diff($value, $value1))) {
                if( $value['id'] == $value1['id'] ) {
                    $arr[$i]=$value1;
                }
                else {
                    $arr[$i]=$value;
                }
            }
        }
        $i++;
    }

Answer 1

This should work for you:

(Here i just simply go trough each innerArray with foreach. Then i get the id from the innerArray and check if it is already in the tmp array and if not i add it to the tmp array. At the end i just simply use array_values(), so that the indexes are clean and starts with 0. The array_reverse() is to get the entire arrray in the right order)

<?php

    $a = array(
            array('id'=>1, 'value'=>2),
            array('id'=>2, 'value'=>3),
            array('id'=>3, 'value'=>4),
            array('id'=>1, 'value'=>5),
            array('id'=>5, 'value'=>10),
            array('id'=>2, 'value'=>6),
    );


    $tmp = array();
    foreach(array_reverse($a) as $v) {
        $id = $v['id'];
        isset($tmp[$id]) or $tmp[$id] = $v;
    }
    $a = array_reverse(array_values($tmp));
    print_r($a);

?>

Output:

Array
(
    [0] => Array
        (
            [id] => 3
            [value] => 4
        )

    [1] => Array
        (
            [id] => 1
            [value] => 5
        )

    [2] => Array
        (
            [id] => 5
            [value] => 10
        )

    [3] => Array
        (
            [id] => 2
            [value] => 6
        )

)