How to remove duplicate values from array in foreach loop? - php

Question

I want to remove duplicate values from array. I know to use array_unique(array) function but faced problem in foreach loop. This is not a duplicate question because I have read several questions regarding this and most of them force to use array_unique(array) function but I have no idea to use it in foreach loop. Here is my php function.
$images = scandir($dir);
$listImages=array();
foreach($images as $image){
$listImages=$image;
echo substr($listImages, 0, -25) ."<br>"; //remove last 25 chracters
}
How to do this?

Answer 1

It is very complicated to remove duplicate values from array within foreach loop. Simply you can push all elements to one array and then remove the duplicates and then get values as you need. Try with following code.
$listImages=array();
$images = scandir($dir);
foreach($images as $image){
$editedImage = substr($image, 0, -25);
array_push($listImages, $editedImage);
}
$filteredList = array_unique($listImages);
foreach($filteredList as $oneitem){
echo $oneitem;
}

Answer 2

The example you provided could be modified as follows:
$images = scandir($dir);
$listImages=array();
foreach($images as $image) {
if (!in_array($image, $listImages)) {
$listImages[] = $image;
}
echo substr($image, 0, -25) ."<br>"; //remove last 25 chracters
}
Now $listImages will contain no duplicates, and it will echo every image (including duplicates).

Answer 3

Based on #mistermartins answer:
$images = scandir($dir);
$listImages=array();
foreach($images as $image) {
//if already echo'd continue to next iteration
if (in_array($image, $listImages)) {
continue;
}
//else, add image to array and echo.
$listImages[] = $image;
echo substr($image, 0, -25) ."<br>"; //remove last 25 chracters
}

Answer 4

It should be faster to use hashmaps:
$images = scandir($dir);
$listImages = array();
foreach($images as $image) {
if (!isset($listImages[$image])) {
$listImages[$image] = true;
echo substr($image, 0, -25) ."<br>"; //remove last 25 chracters
}
}

Answer 5

I'm not sure if I have understood you completely. Subsequent approach worked for me in order to remove duplicate indizes from array using a foreeach loop.
$list = array("hans", "peter", "hans", "lara", "peter", "lara", "lara");
sort($list);
foreach ($list as $k => $v) {
if (isset($check)) {
if ($check === $v) {
unset($list[$k]);
}
}
$check = $v;
}
$noDuplicate = array_values($list);
print_r($noDuplicate);
gives following result:
Array ( [0] => hans [1] => lara [2] => peter )