- array_unshift: documentation ( source)
- array_merge: documentation ( source)
- var_export: documentation ( source)
- array_unique: documentation ( source)
<?php
$value = 2;
$array = [1, 2, 3];
array_unshift($array,$value); // prepend a duplicate
var_export(array_unique($array)); // kill the original
echo "\n---\n";
$value = 2;
$array = [1, 2, 3];
var_export(array_unique(array_merge([$value],$array))); // prepend a duplicate, kill the original