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I've got many answer about this question using other language but i want an answer in php language. Any one help me please This is my array look like

$array = [1, 2, 3, 4, 4, 1, 2, 5, 5, 11, 11];
Anis
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  • Possible duplicate of: https://stackoverflow.com/questions/11340450/select-only-unique-array-values-from-this-array – Peter Abolins Sep 25 '17 at 07:11
  • Not too broad and is a legitimate programming question. Here is one article that seriously considers it: http://www.codinghelmet.com/?path=exercises/number-appearing-once-in-array. Also, I found a related discussion at SO: https://stackoverflow.com/questions/2644179/find-the-only-unpaired-element-in-the-array – slevy1 Sep 25 '17 at 10:49

3 Answers3

6

Use array_count_values() like below:- 

<?php

$array = [1, 2, 3, 4, 4, 1, 2, 5, 5, 11, 11];

$array_count_values = array_count_values($array);// get how many times a value appreas inside array

foreach($array_count_values as $key=>$val){ // now iterate over this newly created array
   if($val ==1){ // if count is 1
     echo $key. " in array come only one time.\n"; // this means value appears only one time inside array
   }
}

Output:- https://eval.in/867433 OR https://eval.in/867434

If you want values in an array:-

<?php

$array = [1, 2, 3, 4, 4, 1, 2, 5, 5, 11, 11,13]; // increased one value to show you the output

$array_count_values = array_count_values($array);

$single_time_comming_values_array = [];
foreach($array_count_values as $key=>$val){
   if($val ==1){
     $single_time_comming_values_array[] =  $key;
   }
}

print_r($single_time_comming_values_array);

Output:- https://eval.in/867515

Alive to die - Anant
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1

Here, you can use something like this-

<?php
function appearedOnce($arr)
{
  $result = 0;

       for($i=0; $i<sizeof($arr); $i++)
       {
          $result =  $result ^ $arr[$i];   

       }
    return $result;
}
$num = array(1, 2, 3, 4, 4, 1, 2, 5, 5, 11, 11);
print_r(appearedOnce($num)."\n")
?>
Alive to die - Anant
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Prashanth kumar
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  • You have a clever solution and it's fast, too! I ran your code at https://3v4l.org/IRfV7#output. If you'd add a brief explanation about how the code works it would improve your answer. – slevy1 Sep 25 '17 at 08:43
0

My initial response was to take a more pedestrian approach which works as you may note from this example. Then I chanced upon a related discussion.

Another approach involves sorting the array and then inspecting pairs of numbers for duplicates. The following code is a result of coupling the OP's array with my translation of the presumably C source code of Michael Martin into PHP, as follows:

<?php

$arr =  [1, 2, 3, 4, 4, 1, 2, 5, 5, 11, 11];

sort($arr);

for($i = 0, $max = count($arr); $i < $max; $i++){

    // is single number last element in array?
    if($i == count($arr)-1)
        $singleNum = $arr[$i];

    // If adjacent elements the same, skip  
    if($i < count($arr)-1 && $arr[$i] == $arr[$i+1]){
        $i++;
    }
    else
    {
        // found single number.
        $singleNum = $arr[$i];
     }
}
var_dump($singleNum);

See live code

slevy1
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