empty value of a key if the array has duplicates - php

Question

i have this array
Array
(
[0] => Array
(
[user_id] => 78
[post_id] => 3
[post_user_added_id] => 2
)
[1] => Array
(
[user_id] => 76
[post_id] => 3
[post_user_added_id] => 16
)
[2] => Array
(
[user_id] => 78
[post_id] => 3
[post_user_added_id] => 12
)
[3] => Array
(
[user_id] => 76
[post_id] => 9
[post_user_added_id] => 15
)
[4] => Array
(
[user_id] => 77
[post_id] => 9
[post_user_added_id] => 15
)
what i want to do is if the key post_id is repeated i just want to empty it and keep one so my final array will look like this
Array
(
[0] => Array
(
[user_id] => 78
[post_id] => 3
[post_user_added_id] => 2
)
[1] => Array
(
[user_id] => 76
[post_id] =>
[post_user_added_id] => 16
)
[2] => Array
(
[user_id] => 78
[post_id] =>
[post_user_added_id] => 12
)
[3] => Array
(
[user_id] => 76
[post_id] => 9
[post_user_added_id] => 15
)
[4] => Array
(
[user_id] => 77
[post_id] =>
[post_user_added_id] => 15
)
i have tried this code but it doesn't seem to work it deletes the whole array
foreach($arry as $k => $v)
{
foreach($arry as $key => $value)
{
if($k != $key && $v['post_id'] == $value['post_id'])
{
unset($arry [$k]);
}
}
}
print_r($arry);

Answer 1

You can perform foreach with ternary operator
$last = null;//this will keep the previous post_id
foreach($arr as &$v){
($last && $last == $v['post_id']) ? ($v['post_id'] = '') : ($last = $v['post_id']);
}
print_r($arr);
Working example :- https://3v4l.org/RiU9J

Answer 2

here try this.
$tempArr = [];
$resArr = [];
foreach($orignalArr as $key=>$obj){
if(in_array($obj['post_id'], $tempArr)){
$obj['post_id'] = '';
$resArr[] = $obj;
}else{
$tempArr[] = $obj['post_id'];
$resArr[] = $obj;
}
}
print_r($resArr);

Answer 3

try this :
// example code
$arrayResult = array();
$arry = [
1 =>
[
'user_id' => 78,
'post_id' => 3,
'post_user_added_id' => 2
],
2=>
[
'user_id' => 76,
'post_id' => 3,
'post_user_added_id' => 16
],
3 =>
[
'user_id' => 78,
'post_id' => 3,
'post_user_added_id' => 12
],
4 =>
[
'user_id' => 76,
'post_id' => 9,
'post_user_added_id' => 15
],
5 =>
[
'user_id' => 77,
'post_id' => 9,
'post_user_added_id' => 15
]];
$final = array();
foreach($arry as $a)
{
if (in_array($a['post_id'], $arrayResult)) {
$a['post_id'] = 0;
}else{
$arrayResult[] = $a['post_id'];
}
$final[] = $a;
}
var_dump($final);

Answer 4

Maybe if you use a stack for comparison?
edit: rewritten the code...
$stack=[];
foreach ($array as $index => $subarray){
if(in_array($subarray['post_id'], $stack)) {
$array[$index]['post_id'] = null;
}
else $stack[]=$subarray['post_id'];
}
print_r($array);
example: https://3v4l.org/FsPUG
Hope this helps!

Answer 5

use of your array value in instead of $arr and try to filter array like the following code :
$arr = array(
array(
'user_id'=>15,
'post_id'=>3,
'post_user_added_id'=>2
),
array(
'user_id'=>16,
'post_id'=>3,
'post_user_added_id'=>2
),
array(
'user_id'=>18,
'post_id'=>3,
'post_user_added_id'=>2
),
array(
'user_id'=>18,
'post_id'=>3,
'post_user_added_id'=>2
),
array(
'user_id'=>16,
'post_id'=>3,
'post_user_added_id'=>2
),
);
$postids = array();
foreach($arr as $key=>$val){
if(in_array($val['post_id'], $postids)){
$arr[$key]['post_id'] = '';
}else{
$postids[] = $val['post_id'];
}
}
echo "<pre>";print_r($arr);exit;
Output :
Array
(
[0] => Array
(
[user_id] => 15
[post_id] => 3
[post_user_added_id] => 2
)
[1] => Array
(
[user_id] => 16
[post_id] =>
[post_user_added_id] => 2
)
[2] => Array
(
[user_id] => 18
[post_id] =>
[post_user_added_id] => 2
)
[3] => Array
(
[user_id] => 18
[post_id] =>
[post_user_added_id] => 2
)
[4] => Array
(
[user_id] => 16
[post_id] =>
[post_user_added_id] => 2
)
)