CODEWITHSUNDEEP
phparraysforeachduplicatesarray-unique
Bandara
Bandara

Reputation: 283

How to remove duplicate values from array in foreach loop?

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?

Upvotes: 3

Views: 15448

Answers (5)

isuru
isuru

Reputation: 3565

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;
   }

Upvotes: 8

Friedrich Siever
Friedrich Siever

Reputation: 469

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 )

Upvotes: 0

danopz
danopz

Reputation: 3408

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
    }
}

Upvotes: 0

Richard Parnaby-King
Richard Parnaby-King

Reputation: 14862

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
}

Upvotes: 1

mister martin
mister martin

Reputation: 6252

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).

Upvotes: 1

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