CODEWITHSUNDEEP
phparrayscounting
mikey_w
mikey_w

Reputation: 1777

Count and display occurrences of unique values in an array

I am working with a one dimensional array in PHP. I would like to detect the presence of duplicate values, then count the number of duplicate values and output the results. For example, given the following array:

$array = [
    'apple',
    'orange',
    'pear',
    'banana',
    'apple',
    'pear',
    'kiwi',
    'kiwi',
    'kiwi'
];

I would like to print:

apple (2)
orange
pear (2)
banana
kiwi (3)

Any advice on how to approach this problem?

Upvotes: 137

Views: 255025

Answers (15)

mickmackusa
mickmackusa

Reputation: 47874

Loop over the keys and values returned by array_count_values() and conditionally print the number of occurrences if greater than one.

Code: (Demo)

foreach (array_count_values($array) as $value => $count) {
    printf("%s%s\n", $value, $count > 1 ? " ($count)" :'');
}

Upvotes: 0

Anton Maryanov
Anton Maryanov

Reputation: 479

function array_not_unique( $a = array() )
{
    return array_diff_key( $a , array_unique( $a ) );
}

Result: (Demo)

array (
  4 => 'apple',
  5 => 'pear',
  7 => 'kiwi',
  8 => 'kiwi',
)

Upvotes: 47

babak-maziar
babak-maziar

Reputation: 23

$arr = [1,2,2,2,4,5,5,5,8,9,10,2,5,9,10,10];
array_count_values($arr); 
// OUT PUT Array(
//    2 => 4
//    5 => 4
//    9 => 2
//   10 => 3
// )

// If you want unique items
$items = array_keys( array_intersect( array_count_values($arr), [1] ) )

//If you want duplicate items 
$duplicates = array_keys( array_diff( array_count_values($arr), [1] ) )

Upvotes: 1

Saif
Saif

Reputation: 27

This function give you the redundant values only

function array_find_redundant($A){
    $U=$N=[];
    foreach($A As $k=>$v){
        if(in_array($v,$U)){$N[$k]=$v;}else{$U[]=$v;}
    }
    return $N;
}

$A = ['A','B','B','C','C','C'];
$B = array_find_redundant($A); // [2=>'B',4=>'C',5=>'C']

Upvotes: 1

Rupess
Rupess

Reputation: 11

function array_not_unique(array $array): array
    {
        $duplicate_array = array_diff_key( $array , array_unique( $array ) );
        $unique_array = [];
        foreach ($array as $key => $value) {
            if ( in_array($value, $duplicate_array)) {
                $duplicate_array[$key] = $value;
            }
            else {
                $unique_array[$key] = $value;
            } 

        }

        return ["unique_array" => $unique_array, "duplicate_array" => $duplicate_array];
    }

Upvotes: 1

Michael Saban
Michael Saban

Reputation: 39

$data = ['outer', 'inner', 'sole', 'sole', 'outer', 'outer'];

$result = max(array_count_values($data));

if($result > 1) {
  echo 'Duplicate items were found!';
}

I think this way is shorter and cleaner.

Upvotes: 1

thelife
thelife

Reputation: 11

A simple method:

$array = array_values(array_unique($array, SORT_REGULAR));

Upvotes: -1

aswine
aswine

Reputation: 207

I didn't find the answer I was looking for, so I wrote this function. This will make an array that contains only the duplicates between the two arrays, but not print the number of times an element is duplicated, so it's not directly answering the question, but I'm hoping it'll help someone in my situation.

function findDuplicates($array1,$array2)
{
    $combined = array_merge($array1,$array2);
    $counted = array_count_values($combined);
    $dupes = [];
    $keys = array_keys($counted);
    foreach ($keys as $key)
    {   
        if ($counted[$key] > 1)
        {$dupes[] = $key;}
    }
    sort($dupes);
    return $dupes;
}
$array1 = [1,2,3,4,5];
$array2 = [4,5,6,7,8];
$dupes = findDuplicates($array1,$array2);
print_r($dupes);

Outputs:

Array
(
    [0] => 4
    [1] => 5
)

Upvotes: 1

Silfverstrom
Silfverstrom

Reputation: 29322

You can use array_count_values function

$array = array('apple', 'orange', 'pear', 'banana', 'apple',
'pear', 'kiwi', 'kiwi', 'kiwi');

print_r(array_count_values($array));

will output

Array
(
   [apple] => 2
   [orange] => 1
   [pear] => 2
   etc...
)

Upvotes: 266

uday
uday

Reputation: 1

$count = 0;
$output ='';
$ischeckedvalueArray = array();
for ($i=0; $i < sizeof($array); $i++) {
    $eachArrayValue = $array[$i];
    if(! in_array($eachArrayValue, $ischeckedvalueArray)) {
        for( $j=$i; $j < sizeof($array); $j++) {
            if ($array[$j] === $eachArrayValue) {
                $count++;
            }
        }
        $ischeckedvalueArray[] = $eachArrayValue;
        $output .= $eachArrayValue. " Repated ". $count."<br/>";
        $count = 0;
    }

}

echo $output;

Upvotes: 0

helpful tip
helpful tip

Reputation:

To get rid use array_unique(). To detect if have any use count(array_unique()) and compare to count($array).

Upvotes: 9

Ritvick Paliwal
Ritvick Paliwal

Reputation: 1

if(count(array_unique($array))<count($array))
{
    // Array has duplicates
}
else
{
    // Array does not have duplicates
}

Upvotes: 131

Simon Scarfe
Simon Scarfe

Reputation: 9618

You could try turning that array into a associative array with the fruits as keys and the number of occurrences as values. Bit long-winded, but it looks like:

$array = array('apple', 'orange', 'pear', 'banana', 'apple',
   'pear', 'kiwi', 'kiwi', 'kiwi');
$new_array = array();
foreach ($array as $key => $value) {
    if(isset($new_array[$value]))
        $new_array[$value] += 1;
    else
        $new_array[$value] = 1;
}
foreach ($new_array as $fruit => $n) {
    echo $fruit;
    if($n > 1)
        echo "($n)";
    echo "<br />";
}

Upvotes: 9

Reputation:

Perhaps something like this (untested code but should give you an idea)?

$new = array();

foreach ($array as $value)
{
    if (isset($new[$value]))
        $new[$value]++;
    else
        $new[$value] = 1;
}

Then you'll get a new array with the values as keys and their value is the number of times they existed in the original array.

Upvotes: 2

Anton Gogolev
Anton Gogolev

Reputation: 115721

Stuff them into a map (pseudocode)

map[string -> int] $m
foreach($word in $array)
{
    if(!$m.contains($word))
        $m[$word] = 0;

    $m[$word] += 1;
}

Upvotes: 1

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