Array unique values PHP - php

Question

I want to find the Unique values by username:
so the resulting array would be [0] =>JakeP, [1]=>TomC
My code currently works, but I was wondering is there a better way to accomplish this task with less loops, or using array_unique function?
Array
(
[0] => Array
(
[ID] => 3
[Username] => TomC
[Project_Name] => Inventory
)
[1] => Array
(
[ID] => 4
[Username] => JakeP
[Project_Name] => Inventory
)
[2] => Array
(
[ID] => 2
[Username] => TomC
[Project_Name] => Stocks
)
[3] => Array
(
[ID] => 1
[Username] => Tomc
[Project_Name] => Stocks
)
)
My code which works is :
$names_filter = array();
foreach($latest_projects as $project)
{
if(empty($names_filter))
{
$names_filter[] = $project['Username'];
}
else {
foreach($names_filter as $key=>$value)
{
if($value == $project['Username'])
{ break; }
else
{
$names_filter[] = $project['Username'];
}
}
}
}

Answer 1

If you're using PHP >= 5.5 you can take advantage of the array_column() function:
$uniqueNames = array_unique(
array_column($myArray, 'Username')
);
Prior to PHP 5.5, you can use:
$uniqueNames = array_unique(
array_map(
function($value) {
return $value['Username'];
},
$myArray
)
);

Answer 2

You can use the in_array function to simplify your code. Example:
$names_filter = array();
foreach($latest_projects as $project)
{
if(!in_array($project['Username'], $names_filter))
{
$names_filter[] = $project['Username'];
}
}
The in_array() function checks for the existence of a value in an array. So the foreach loop will only add a project username to the $names_filter array if it's not in the array. The output should be a list of unique usernames in the $names_filter array.

Answer 3

We can loop through $latest_projects and store each user name to new array ($filter). Since array can't have two elements with same keys, if the key exists it will be overwritten.
$filter = array();
foreach ($latest_projects as $project)
{
$filter[$project['Username']] = 1;
}
$filter = array_keys($filter);

Answer 4

I can't speak to the performance of this over other solutions, but a similar effect can be achieved with the use of array_map and array_unique. It's not as readable either though, which is just as important.
$uniqueUsers = array_unique(array_map(function ($p) { return $p['Username']; }, $latest_projects));