Unique PHP Array - php

Question

How can I check if the values are unique in an array based on the key value? Below is the out put of the array. I want to remove duplicate values based on the "id" key. If you check below, the 2nd & 3rd array are same except for the "role" value. Because of this, array_unique is not working on this array.
array
0 =>
array
'id' => string '1521422' (length=7)
'name' => string 'David Alvarado' (length=14)
'role' => string 'associate producer ' (length=20)
1 =>
array
'id' => string '0098210' (length=7)
'name' => string 'Cristian Bostanescu' (length=19)
'role' => string 'line producer: Romania (as Cristi Bostanescu)' (length=46)
2 =>
array
'id' => string '1266015' (length=7)
'name' => string 'Bruno Hoefler' (length=13)
'role' => string 'co-producer ' (length=13)
3 =>
array
'id' => string '1266015' (length=7)
'name' => string 'Bruno Hoefler' (length=13)
'role' => string 'executive producer ' (length=20)
4 =>
array
'id' => string '1672379' (length=7)
'name' => string 'Alwyn Kushner' (length=13)
'role' => string 'associate producer ' (length=20)

Answer 1

Try this one:
<?php
$array = array(
array('id' => 1, 'text' => 'a'),
array('id' => 2, 'text' => 'b'),
array('id' => 1, 'text' => 'c'),
array('id' => 3, 'text' => 'd')
);
$array = array_filter($array, function ($item) {
static $found = array();
if (isset($found[$item['id']])) return false;
$found[$item['id']] = true;
return true;
});
var_dump($array);
This works as of PHP 5.3 (because of the closure and static statement).
cf. http://php.net/manual/en/function.array-filter.php for more information. I tested the statement within loops, it works there as well.

Answer 2

Basically you want to implement a variation of array_unique that does what you want:
function array_unique_multi($arr,$key='id') {
// $arr is the array to work on
// $key is the key to make unique by
$ret = Array();
foreach($arr as $v) {
if( !isset($ret[$v[$key]])) $ret[$v[$key]] = $k;
}
return array_values($ret);
}

Answer 3

You can use this code:
// assuming $arr is your original array
$narr = array();
foreach($arr as $key => $value) {
//$narr[json_encode($value)] = $key;
if (!array_key_exists($value["id"], $narr))
$narr[$value["id"]] = $key;
}
$narr = array_flip($narr);
foreach($arr as $key => $value) {
if (!array_key_exists($key, $narr))
unset($arr[$key]);
}
print_r($arr); // will have no duplicates