array_count_values

(PHP 4, PHP 5, PHP 7, PHP 8)

array_count_values — Conta tutti i valori di un array

Descrizione

array_count_values(array $array): array

array_count_values() restituisce un array usando i valori di array come chiavi e la loro frequenza in array come valori.

Elenco dei parametri

array: L'array di valori da contare

Valori restituiti

Restituisce un array associativo di valori da array come chiavi ed il loro conteggio come valore.

Errori/Eccezioni

Lancia un E_WARNING per ogni elemento che non è string o int.

Esempi

Example #1 Esempio di array_count_values()

<?php
$array = array(1, "ciao", 1, "mondo", "ciao");
print_r(array_count_values($array));
?>

Il precedente esempio visualizzerà:

Array
(
    [1] => 2
    [ciao] => 2
    [mondo] => 1
)

Vedere anche:

count() - Conta gli elementi in una variabile, o le proprietà in un oggetto
array_unique() - Rimuove i valori duplicati di un array
array_values() - Restituisce tutti i valori di un array
count_chars() - Restituisce informazioni sui caratteri usati in una stringa

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User Contributed Notes 15 notes

down

sergolucky96 at gmail dot com ¶

5 years ago


Simple way to find number of items with specific values in multidimensional array:

<?php

$list = [
  ['id' => 1, 'userId' => 5],
  ['id' => 2, 'userId' => 5],
  ['id' => 3, 'userId' => 6],
];
$userId = 5;

echo array_count_values(array_column($list, 'userId'))[$userId]; // outputs: 2
?>

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anvil_sa at NOSPAMNO dot hotmail dot com ¶

3 years ago


Based on sergolucky96 suggestion 
Simple way to find number of items with specific *boolean* values in multidimensional array:

<?php

$list = [
  ['id' => 1, 'result' => true],
  ['id' => 2, 'result' => true],
  ['id' => 3, 'result' => false],
];
$result = true;

echo array_count_values(array_map(function($v) {return $v?'true':'false';},array_column($list, 'result')))[$result]
// outputs: 2

?>

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szczepan.krolgmail.c0m ¶

13 years ago


Here is a Version with one or more arrays, which have similar values in it:

Use $lower=true/false to ignore/set case Sensitiv.



<?php



$ar1[] = array("red","green","yellow","blue");

$ar1[] = array("green","yellow","brown","red","white","yellow");

$ar1[] = array("red","green","brown","blue","black","yellow");

#$ar1= array("red","green","brown","blue","black","red","green"); // Possible with one or multiple Array



$res = array_icount_values ($ar1);

print_r($res);



function array_icount_values($arr,$lower=true) {

     $arr2=array();

     if(!is_array($arr['0'])){$arr=array($arr);}

     foreach($arr as $k=> $v){

      foreach($v as $v2){

      if($lower==true) {$v2=strtolower($v2);}

      if(!isset($arr2[$v2])){

          $arr2[$v2]=1;

      }else{

           $arr2[$v2]++;

           }

    }

    }

    return $arr2;

}

/*

Will print:

Array

(

    [red] => 3

    [green] => 3

    [yellow] => 4

    [blue] => 2

    [brown] => 2

    [white] => 1

    [black] => 1

)

*/

?>

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-1

Dominic Vonk ¶

9 years ago


The case-insensitive version:

<?php
function array_count_values_ci($array) {
    $newArray = array();
    foreach ($array as $values) {
        if (!array_key_exists(strtolower($values), $newArray)) {
            $newArray[strtolower($values)] = 0;
        }
        $newArray[strtolower($values)] += 1;
    }
    return $newArray;
}
?>

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-1

rabies dot dostojevski at gmail dot com ¶

16 years ago


I couldn't find a function for counting the values with case-insensitive matching, so I wrote a quick and dirty solution myself:

<pre><?php
function array_icount_values($array) {
    $ret_array = array();
    foreach($array as $value) {
        foreach($ret_array as $key2 => $value2) {
            if(strtolower($key2) == strtolower($value)) {
                $ret_array[$key2]++;
                continue 2;
            }
        }
        $ret_array[$value] = 1;
    }
    return $ret_array;
}

$ar = array('J. Karjalainen', 'J. Karjalainen', 60, '60', 'J. Karjalainen', 'j. karjalainen', 'Fastway', 'FASTWAY', 'Fastway', 'fastway', 'YUP');
$ar2 = array_count_values($ar); // Normal matching
$ar = array_icount_values($ar); // Case-insensitive matching
print_r($ar2);
print_r($ar);
?></pre>

This prints:

Array
(
    [J. Karjalainen] => 3
    [60] => 2
    [j. karjalainen] => 1
    [Fastway] => 2
    [FASTWAY] => 1
    [fastway] => 1
    [YUP] => 1
)
Array
(
    [J. Karjalainen] => 4
    [60] => 2
    [Fastway] => 4
    [YUP] => 1
)

I don't know how efficient it is, but it seems to work. Needed this function in one of my scripts and thought I would share it.

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-2

[Mr.A] ¶

18 years ago


I find a very simple solution to count values in multidimentional arrays (example for 2 levels) :

foreach ($array as $a) {
  foreach ($a as $b) {
    $count_values[$b]++;
  }
}

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-8

Hayley Watson ¶

15 years ago


Yet Another case-insensitive version of array_count_values()

<?php
$ar = array('J. Karjalainen', 'J. Karjalainen', 60, '60', 'J. Karjalainen', 'j. karjalainen', 'Fastway', 'FASTWAY', 'Fastway', 'fastway', 'YUP');

$ar = array_count_values(array_map('strtolower', $ar));
?>

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-4

jekkilekki at gmail dot com ¶

6 years ago


Simple example to count the values of a $key in an associative array:

/**
 * Associative Array Count Values
 * 
 * Returns an array containing the number of values for a given $key in a given associative $array
 * 
 * @param array $array The associative array to count values for
 * @param String $key The key to count values for
 * @return array A new array containing the counted values for the key in the original associative array
 */
function assc_array_count_values( $array, $key ) {
     foreach( $array as $row ) {
          $new_array[] = $row[$key];
     }
     return array_count_values( $new_array );
}

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-6

majerm at gmail dot com ¶

16 years ago


<?
function array_icount_values($array) {
    $ret_array = array();
    foreach($array as $value) $ret_array[strtolower($value)]++;
    return $ret_array;
}

$ar = array('J. Karjalainen', 'J. Karjalainen', 60, '60', 'J. Karjalainen', 'j. karjalainen', 'Fastway', 'FASTWAY', 'Fastway', 'fastway', 'YUP');
$ar = array_icount_values($ar);
?>

this prints:

Array
(
    [j. karjalainen] => 4
    [60] => 2
    [fastway] => 4
    [yup] => 1
)

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-7

bluej100@gmail ¶

15 years ago


byron at byronrode dot co dot za, here are some benchmarks.



<?php

$haystack = Array();

for ($i = 0; $i < 1000000; $i++) {

  $haystack[] = rand(1, 2000);

}



$needle = rand(1, 2000);



echo "__array_count_values()__\n";

$start = microtime(true);

$startmem = memory_get_usage();

$counts = array_count_values($haystack);

$mem = memory_get_usage()-$startmem;

echo 'Count:'.$counts[$needle]."\n";

echo 'Time:'.(microtime(true) - $start)."\n";

echo 'Memory:'.$mem."\n\n";



echo "__array_keys()__\n";

$start = microtime(true);

$startmem = memory_get_usage();

$keys = array_keys($haystack, $needle);

$mem = memory_get_usage()-$startmem;

echo 'Count:'.count($keys)."\n";

echo 'Time:'.(microtime(true) - $start)."\n";

echo 'Memory:'.$mem."\n\n";



echo '__$needle_array[]__'."\n";

$start = microtime(true);

$startmem = memory_get_usage();

$x = count($haystack);

for($i = 0; $i < $x; $i++){

  if($haystack[$i] == $needle){

    $needle_array[] = $haystack[$i];

  }

}

$mem = memory_get_usage()-$startmem;

$number_of_instances = count($needle_array);

echo 'Count:'.$number_of_instances."\n";

echo 'Time:'.(microtime(true) - $start)."\n";

echo 'Memory:'.$mem."\n\n";



echo '__$number_of_instances++__'."\n";

$start = microtime(true);

$startmem = memory_get_usage();

$x = count($haystack);

$number_of_instances = 0;

for($i = 0; $i < $x; $i++){

  if($haystack[$i] == $needle){

    $number_of_instances++;

  }

}

$mem = memory_get_usage()-$startmem;

echo 'Count:'.$number_of_instances."\n";

echo 'Time:'.(microtime(true) - $start)."\n";

echo 'Memory:'.$mem."\n\n";

?>



[www]mytemp$ php array_count_test.php

__array_count_values()__

Count:515

Time:0.0607650279999

Memory:120328



__array_keys()__

Count:515

Time:0.0869138240814

Memory:33016



__$needle_array[]__

Count:515

Time:0.259949922562

Memory:24792



__$number_of_instances++__

Count:515

Time:0.258481025696

Memory:0



However, when you use an array of strings by calling md5(rand(1, 2000)), the performance boosts become less significant:



__array_count_values()__

Count:499

Time:0.491794109344

Memory:184328



__array_keys()__

Count:499

Time:0.36399102211

Memory:30072



__$needle_array[]__

Count:499

Time:0.568728923798

Memory:22104



__$number_of_instances++__

Count:499

Time:0.574353933334

Memory:0



Results are similar for string->string haystacks with foreach traversal.

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-7

pmarcIatIgeneticsImedIharvardIedu ¶

20 years ago


array_count_values function does not work on multidimentional arrays.
If $score[][] is a bidimentional array, the command
"array_count_values ($score)" return the error message "Warning: Can only count STRING and INTEGER values!".

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-8

jakubplus at gmail dot com ¶

9 years ago


In order to apply array_map with callback checking for localised values like city name, country name, you have to provide some sort of comparison array.

Here's an example of array_count_values for Polish city names. Just switch array_keys / array_values in order to obtain lowercase / uppercase.

$arr = array('Warsaw', 'Warsaw', 'Wrocław', 'Poznań', 'KrakÓw', 'waRsaw', 'Gdańsk', 'poznań', 'WROCŁAW', 'kraków', 'GDAŃSK');
$lowertoupperpolish = array(
    'ą' => 'Ą',
    'ć' => 'Ć',
    'ę' => 'Ę',
    'ł' => 'Ł',
    'ń' => 'Ń',
    'ó' => 'Ó',
    'ś' => 'Ś',
    'ż' => 'Ż',
    'ź' => 'Ź',
);
function lowers($n) {
    global $lowertoupperpolish;
    return strtolower(str_replace(array_values($lowertoupperpolish), array_keys($lowertoupperpolish), $n));
}
$result = array_count_values(array_map('lowers', $arr));

print_r($result); ...prints:

Array ( [warsaw] => 3 [wrocław] => 2 [poznań] => 2 [kraków] => 2 [gdańsk] => 2 )

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-10

manuzhai (AT) php (DOT) net ¶

20 years ago


You might use serialize() to serialize your objects before analyzing their frequency. :)

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-12

dhairya lakhera ¶

7 years ago


$array = array(1, true, 1, true, false,NULL);
var_dump(array_count_values($array));

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

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-24

coda at bobandgeorge dot com ¶

17 years ago


alwaysdrunk's comment only works if you can trust the client web browser. Using this function doesn't validate that every necessary field exists -- only that every field that was submitted has a value in it. Thus if an attacker wished to force a null value into one of the fields, he could (rather easily) construct a modified form without the field and submit THAT.

Besides, you really ought to be validating each field anyway if you're taking user input.

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