php - How do I count occurrence of duplicate items in array

Solution:

if you want to try without'array_count_values' you can do with a smart way here

<?php
$input= array(12,43,66,21,56,43,43,78,78,100,43,43,43,21);

$count_values = array();
foreach ($input as $a) {

     @$count_values[$a]++;

}
echo 'Duplicates count: '.count($count_values);
print_r($count_values);
?>
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Solution:

Simplest solution (that's where PHP rocks) - ONLY duplicates:

$r = array_filter(array_count_values($array), function($v) { return $v > 1; });
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and check:

print_r($r);
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Result$r:

[43] => 6
[21] => 2
[78] => 2
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Solution:

If you have a multi-dimensional array you can use on PHP 5.5+ this:

array_count_values(array_column($array, 'key'))
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which returns e.g.

 [
   'keyA' => 4,
   'keyB' => 2,
 ]
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Solution:

I actually wrote a function recently that would check for a substring within an array that will come in handy in this situation.

function strInArray($haystack, $needle) {
    $i = 0;
    foreach ($haystack as $value) {
        $result = stripos($value,$needle);
        if ($result !== FALSE) return TRUE;
        $i++;
    }
    return FALSE;
}

$array = array(12,43,66,21,56,43,43,78,78,100,43,43,43,21);

for ($i = 0; $i < count($array); $i++) {
    if (strInArray($array,$array[$i])) {
        unset($array[$i]);
    }
}
var_dump($array);
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Solution:

You can also use it with text items array, u will get number of duplicates properly, but PHP shows

Warning: array_count_values(): Can only count STRING and INTEGER values!

$domains = 
array (
  0 => 'i1.wp.com',
  1 => 'i1.wp.com',
  2 => 'i2.wp.com',
  3 => 'i0.wp.com',
  4 => 'i2.wp.com',
  5 => 'i2.wp.com',
  6 => 'i0.wp.com',
  7 => 'i2.wp.com',
  8 => 'i0.wp.com',
  9 => 'i0.wp.com' );

$tmp = array_count_values($domains);
print_r ($tmp);

    array (
      'i1.wp.com' => 2730,
      'i2.wp.com' => 2861,
      'i0.wp.com' => 2807
    )
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Solution:

Count duplicate element of an array in PHP without using in-built function

$arraychars=array("or","red","yellow","green","red","yellow","yellow");
$arrCount=array();
        for($i=0;$i<$arrlength-1;$i++)
        {
          $key=$arraychars[$i];
          if($arrCount[$key]>=1)
            {
              $arrCount[$key]++;
            } else{
              $arrCount[$key]=1;
        }
        echo $arraychars[$i]."<br>";
     }
        echo "<pre>";
        print_r($arrCount);
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Solution:

There is a magical function PHP is offering to you it called in_array().

Using parts of your code we will modify the loop as follows:

<?php
$array = array(12,43,66,21,56,43,43,78,78,100,43,43,43,21);
$arr2 = array();
$counter = 0;
for($arr = 0; $arr < count($array); $arr++){
    if (in_array($array[$arr], $arr2)) {
        ++$counter;
        continue;
    }
    else{
        $arr2[] = $array[$arr];
    }
}
echo 'number of duplicates: '.$counter;
print_r($arr2);
?>
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The above code snippet will return the number total number of repeated items i.e. form the sample array 43 is repeated 5 times, 78 is repeated 1 time and 21 is repeated 1 time, then it returns an array without repeat.

Solution:

You can do it using foreach loop. (Demo)

$array = array(1,2,3,1,2,3,1,2,3,4,4,5,6,4,5,6,88);
$set_array = array();
foreach ($array as $value) {
    $set_array[$value]++;
}
print_r($set_array);     
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Output:

Warning: Undefined array key 1 in /in/aGPqe on line 6

Warning: Undefined array key 2 in /in/aGPqe on line 6

Warning: Undefined array key 3 in /in/aGPqe on line 6

Warning: Undefined array key 4 in /in/aGPqe on line 6

Warning: Undefined array key 5 in /in/aGPqe on line 6

Warning: Undefined array key 6 in /in/aGPqe on line 6

Warning: Undefined array key 88 in /in/aGPqe on line 6
Array
(
    [1] => 3
    [2] => 3
    [3] => 3
    [4] => 3
    [5] => 2
    [6] => 2
    [88] => 1
)
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Solution:

I came here from google looking for a way to count the occurrence of duplicate items in an array. Here is the way to do it simply:

$colors = ["red", "green", "blue", "red", "yellow", "blue"];

$unique_colors = array_unique($colors);                // ["red", "green", "blue", "yellow"]
$duplicates = count($colors) - count($unique_colors);  // 6 - 4 = 2

if ($duplicates == 0) {
    echo "There are no duplicates";
}
echo "No. of Duplicates: " . $duplicates;

// Output: No. of Duplicates are: 2
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How array_unique() works?

It elements all the duplicates. ex: Lets say we have an array as follows -

$cars = array( [0]=>"lambo", [1]=>"ferrari", [2]=>"Lotus", [3]=>"ferrari", [4]=>"Bugatti");

When you do$cars = array_unique($cars); cars will have only following elements.$cars = array( [0]=>"lambo", [1]=>"ferrari", [2]=>"Lotus", [4]=>"Bugatti");

To read more: https://www.php.net/manual/en/function.array-unique.php

Solution:

this code will return duplicate value in same array

$array = array(12,43,66,21,56,43,43,78,78,100,43,43,43,21);
foreach($arr as $key=>$item){
  if(array_count_values($arr)[$item] > 1){
     echo "Found Matched value : ".$item." <br />";
  }
}
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Solution:

$search_string = 4;
$original_array = [1,2,1,3,2,4,4,4,4,4,10];
$step1 = implode(",", $original_array); // convert original_array to string
$step2 = explode($search_string, $step1); // break step1 string into a new array using the search string as delimiter
$result = count($step2)-1; // count the number of elements in the resulting array, minus the first empty element
print_r($result); // result is 5
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Solution:

    $input = [1,2,1,3,2,4,10];
    //if give string
    //$input = "hello hello how are you how hello";
    //$array = explode(' ',$input);
    $count_val = [];
    foreach($array as $val){
      $count_val[$val]++;
    }
    print_r($count_val);
//output ( [1] => 2 [2] => 2 [3] => 1 [4] => 1 [10] => 1 )
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