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array_count_values

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

array_count_values配列内に存在する、異なる値の出現回数を数える

説明

array_count_values(array $array): array

array_count_values() は、 配列 array の値 (数値または文字列でなければいけません) をキーとし、 array におけるその値の出現回数を値とした配列を返します。

パラメータ

array

値を数える配列。

戻り値

array のキーとその登場回数を組み合わせた連想配列を返します。

エラー / 例外

string あるいは int 以外の型の要素が登場するたびに E_WARNING が発生します。

例1 array_count_values() の例

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

上の例の出力は以下となります。

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

参考

  • count() - 配列または Countable オブジェクトに含まれるすべての要素の数を数える
  • array_unique() - 配列から重複した値を削除する
  • array_values() - 配列の全ての値を返す
  • count_chars() - 文字列で使用されている文字に関する情報を返す

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User Contributed Notes 8 notes

up
28
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
6
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
4
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
0
Rmr
5 months ago
If you have a multidimensional array with unknown dimensions, you cannot use this function, use instead:

<?php
function array_count_recursive(array $arr): array {
$occurrences = [] ;
array_walk_recursive( $arr, function($value, $key) use (&$occurrences) {
@
$occurrences[$value]++;
// @ to surpress warnings "Undefined array key". In php8 you can also use
// $occurrences[$value] = ($occurrences[$value] ?? 0) + 1
});
return
$occurrences;
}
?>
up
0
tyler at tloc dot com
1 year ago
A cleaner way to use array_count_values() to find boolean counts.

<?php

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

echo
array_count_values(array_map('intval', array_column($list, 'result')))[(int)$result];
// outputs: 2
?>
up
-1
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
-3
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
-4
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;
}
?>
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