array_count_values

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

array_count_valuesCounts the occurrences of each distinct value in an array

Description

array_count_values(array $array): array

array_count_values() returns an array using the values of array (which must be ints or strings) as keys and their frequency in array as values.

Parameters

array

The array of values to count

Return Values

Returns an associative array of values from array as keys and their count as value.

Errors/Exceptions

Throws E_WARNING for every element which is not string or int.

Examples

Example #1 array_count_values() example

<?php
$array
= array(1, "hello", 1, "world", "hello");
print_r(array_count_values($array));
?>

The above example will output:

Array
(
    [1] => 2
    [hello] => 2
    [world] => 1
)

See Also

  • count() - Counts all elements in an array or in a Countable object
  • array_unique() - Removes duplicate values from an array
  • array_values() - Return all the values of an array
  • count_chars() - Return information about characters used in a string

add a note add a note

User Contributed Notes 15 notes

up
21
sergolucky96 at gmail dot com
6 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
?>
up
1
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

?>
up
0
szczepan.krolgmail.c0m
14 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
)
*/
?>
up
-1
Dominic Vonk
10 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;
}
?>
up
-1
rabies dot dostojevski at gmail dot com
17 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.
up
-2
[Mr.A]
19 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]++;
  }
}
up
-8
Hayley Watson
16 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));
?>
up
-4
jekkilekki at gmail dot com
7 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( $new_array );
}
up
-6
majerm at gmail dot com
16 years ago
<?
function array_icount_values($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
)
up
-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.
up
-7
pmarcIatIgeneticsImedIharvardIedu
21 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!".
up
-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 )
up
-10
manuzhai (AT) php (DOT) net
21 years ago
You might use serialize() to serialize your objects before analyzing their frequency. :)
up
-12
dhairya lakhera
8 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!
up
-24
coda at bobandgeorge dot com
18 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.
To Top