array_count_values

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

array_count_valuesConta 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

up
21
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
?>
up
1
anvil_sa at NOSPAMNO dot hotmail dot com
2 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
12 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
8 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
15 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]
17 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
14 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
5 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( $new_array );
}
up
-6
majerm at gmail dot com
15 years ago
<?
function array_icount_values($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
14 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
19 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
8 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
20 years ago
You might use serialize() to serialize your objects before analyzing their frequency. :)
up
-12
dhairya lakhera
6 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
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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