How to find duplicated values in PHP arrays?

Question

I have an array like this

$a=array(0=>1,1=>1,2=>5,3=>5,4=>10)

Now I want to find out the duplicate values and add those in to an array like this:

array_push($arrayOfones,$a['0'],$a['1'];
array_push($arrayOfFive,$a['2'],$a['5'];

$a['0'], $a['1'], $a['2'] and $a['5'] are not valid as shown in your code — Alvin Wong
– Alvin Wong, Commented Oct 23, 2012 at 7:12

xdazz · Accepted Answer · 2012-10-23 07:23:16Z

3

You could take a look at array_count_values

$ret = array_count_values($a);

// get the duplicate values
$ret = array_filter($ret, function ($var) {
  return $var > 1;
});

array_walk($ret, function(&$var, $key) {
  $var = array_fill(0, $var, $key);
});

var_dump($ret); // $ret[1] is $arrayOfOnes, $ret[5] is $arrayOfFive

edited Oct 23, 2012 at 7:23

answered Oct 23, 2012 at 7:14

xdazz

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Comments

Angelin Nadar · Accepted Answer · 2012-10-24 06:26:45Z

1

little simpler with no array functions other than count():

foreach($a as $key=>$value){
    $ip[$value][] = $key;
}

foreach($ip as $key=>$inner_arr){  
    if(count($inner_arr) > 1)
    $dup[$key] = $inner_arr ;
}

edited Oct 24, 2012 at 6:26

answered Oct 23, 2012 at 7:17

Angelin Nadar

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Comments

Ertunç · Accepted Answer · 2012-10-23 16:42:05Z

0

    $a=array(0=>1,1=>1,2=>5,3=>5,4=>10); 
    $c=0;
    foreach ($a as $key => $row) {

        if (!isset($rs[$row])) {
            $rs[$row][$key]= $key;
             $c = 1;
             $res[$row]['count'] = $c;
             $res[$row]['values'][$key] = $key;
        } 
        else {
            $res[$row]['count']++;
            $res[$row]['values'][$key] = $key;
        }
    }

answered Oct 23, 2012 at 16:42

Ertunç

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