(PHP 4, PHP 5, PHP 7)

count変数に含まれるすべての要素、 あるいはオブジェクトに含まれる何かの数を数える


int count ( mixed $array_or_countable [, int $mode = COUNT_NORMAL ] )

変数に含まれるすべての要素、 あるいはオブジェクトに含まれる何かの数を数えます。

オブジェクトに対して、もし SPL がインストールされている場合、インターフェイス Countable を実装することで count() にフックすることができます。このインターフェイスには 1 つのメソッド Countable::count() があり、count() 関数に対する値を返します。

配列の実装やPHPでの使用法に関する詳細な説明については、マニュアルの 配列のセクションを参照ください。



配列あるいは Countable オブジェクト。


オプションのmode 引数が COUNT_RECURSIVE (または 1) にセットされた場合、count() は再帰的に配列をカウントします。 これは多次元配列の全ての要素をカウントするといった場合に特に有効です。


count() は、再帰を検出して無限ループを回避するようになっています。 しかしその場合 (配列の中に自分自身が複数回登場する場合) は毎回 E_WARNING を発行し、期待する結果より大きい数を返します。


array_or_countable に含まれる要素の数を返します。 もしパラメータが配列もしくは Countable インターフェイスを実装したオブジェクトではない場合、 1 が返されます。 ひとつ例外があり、array_or_countableNULL の場合、 0 が返されます。


count() は、セットされていない変数に関して 0 を返しますが、変数が空の配列として初期化されている場合にも 0 を返します。 ある変数がセットされているかどうかを調べるには、 isset() を使用してください。

例1 count() の例

[0] = 1;
$a[1] = 3;
$a[2] = 5;
$result count($a);
// $result == 3

$b[0]  = 7;
$b[5]  = 9;
$b[10] = 11;
$result count($b);
// $result == 3

$result count(null);
// $result == 0

$result count(false);
// $result == 1

例2 再帰的な count() の例

= array('fruits' => array('orange''banana''apple'),
'veggie' => array('carrot''collard''pea'));

// 再帰的なカウント
echo count($foodCOUNT_RECURSIVE); // output 8

// 通常のカウント
echo count($food); // output 2



  • is_array() - 変数が配列かどうかを検査する
  • isset() - 変数がセットされていること、そして NULL でないことを検査する
  • strlen() - 文字列の長さを得る

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User Contributed Notes 19 notes

9 months ago
As I see in many codes, don't use count to iterate through array.
Onlyranga says you could declare a variable to store it before the for loop.
I agree with his/her approach, using count in the test should be used ONLY if you have to count the size of the array for each loop.

You can do it in the for loop too, so you don't have to "search" where the variable is set.
= [1, 5, 'element'];
$i = 0, $c = count($array); $i < $c; $i++)
onlyranga at gmail dot com
1 year ago
If you want to run through large arrays don't use count() function in the loops , its a over head in performance,  copy the count() value into a variable and use that value in loops for a better performance.


// Bad approach

    // calculations

// Good approach

$arr_length = count($some_arr);
    // calculations
array at from dot pl
11 months ago
onlyranga at gmail dot com note about keeping count() in variable is not really correct, For some time now using variable and calling `count()` on each loop iteration costs you basically the same.

Proof: If you look into PHP sources then you see that for some time now it returns internal counter value instead of counting on each call. Here is `count` implementation: [1] where for array it calls `php_count_recursive` [2] which is then calls zend_hash_num_elements and returns `nNumOfElements` internal variable. It is not counting anything.

You may want to read this blog post about PHP internals too:

alexandr at vladykin dot pp dot ru
9 years ago
My function returns the number of elements in array for multidimensional arrays subject to depth of array. (Almost COUNT_RECURSIVE, but you can point on which depth you want to plunge).

function getArrCount ($arr, $depth=1) {
      if (!
is_array($arr) || !$depth) return 0;
      foreach (
$arr as $in_ar)
$res+=getArrCount($in_ar, $depth-1);
Gerd Christian Kunze
2 years ago
Get maxWidth and maxHeight of a two dimensional array..?

1st dimension = Y (height)
2nd dimension = X (width)
e.g. rows and cols in database result arrays

= array( 0 => array( 'key' => 'value', ...), ... );

So for Y (maxHeight)
= count( $TwoDimensionalArray )

And for X (maxWidth)
= max( array_map( 'count'$TwoDimensionalArray ) );

Simple? ;-)
danny at dannymendel dot com
8 years ago
I actually find the following function more useful when it comes to multidimension arrays when you do not want all levels of the array tree.

// $limit is set to the number of recursions
function count_recursive ($array, $limit) {
$count = 0;
    foreach (
$array as $id => $_array) {
        if (
is_array ($_array) && $limit > 0) {
$count += count_recursive ($_array, $limit - 1);
        } else {
$count += 1;
8 months ago
A function of one line to find the number of elements that are not arrays, recursively :

function count_elt($array, &$count=0){
  foreach($array as $v) if(is_array($v)) count_elt($v,$count); else ++$count;
  return $count;
atoi_monte at hotmail dot com
8 years ago
Please note: While SPL is compiled into PHP by default starting with PHP 5, the Countable interface is not available until 5.1
semmelbroesel at gmail dot com
2 years ago
I've read this somewhere else before, but experienced it first hand now, so I thought I'd post it here.

While in regular use, count() is pretty fast, this changes rapidly when used in a for loop. Example:

for ($x = 0; $x < count($array); $x++)
  // some code here

If your array contains a lot of data, this code gets slowed down significantly. Better way to write this:

$arrayCount = count($array);
for ($x = 0; $x < $arrayCount; $x++)
  // some code here

I didn't think it would make such a difference, but it did in my case - changed 15 seconds load time into 1 second!
pjrfigueiredo at gmail dot com
7 months ago
PHP - count an object returns 1?
This is how: $total = count((array)$objecto);
jezdec at email dot cz
6 years ago
Hi there,
there is a simple script with example for counting rows and columns of a two-dimensional array.

= array(
"apples" =>
"red", "yellow", "pineapples"),
"bananas" =>
"small", "medium", "big"),
"vegs" =>
"potatoes", "carrots", "onions")

$rows = count($data,0);
$cols = (count($data,1)/count($data,0))-1;
"There are {$rows} rows and {$cols} columns in the table!";
1 year ago
If you want to check whether large arrays contain a specific (less) number of array elements, don't use count(). This is very slow because each element has to get iterated.

This is much faster:

function isArrayCount(array $array, $count) {
    $count = (int) $count;
    $result = reset($array);
    if ($count === 0) {
        // for empty arrays reset returns FALSE
        // we have to switch the boolean result
        $result = !$result;
    for($i = 1; $i < $count; $i++) {
        if (next($array) === FALSE) {
            $result = FALSE;
    return $result;
1 month ago
About 2d arrays, you have many way to count elements :

= array ( array(1,2,3),
'a','b','c','d') );

// All elements
echo count($MyArray ,COUNT_RECURSIVE);  // output 11 (9 values + 2 arrays)

// First level elements
echo count($MyArray );                  // output 4 (2 values+ 2 arrays)

// Both level values, but only values
echo(array_sum(array_map('count',$MyArray ))); //output 9 (9 values)

// Only second level values
echo (count($MyArray ,COUNT_RECURSIVE)-count($MyArray )); //output 7 ((all elements) - (first elements))
lopezvit at gmail dot com
2 years ago
I think that maybe that is faster (I don't know why, because, at least in C, for loops are faster than while ones due to compile optimization) but what is sure is that, in case the list is empty, you are going to iterate over the loop at least one. And I'm sure that is not what you want to do. The correct way in this occassion is to use a normal while, not a do, while.
freefaler at gmail dot com
11 years ago
If you want to count only elements in the second level of 2D arrays.A close to mind note, useful for multidimentional arrays:

= array('fruits' => array('orange', 'banana', 'apple'),
'veggie' => array('carrot', 'collard','pea'));

// recursive count
echo count($food,COUNT_RECURSIVE);  // output 8

// normal count
echo count($food);                  // output 2

// all the fruits and veggies
echo (count($food,COUNT_RECURSIVE)-count($food,0)); //output 6
MaxTheDragon at home dot nl
2 years ago
If you wish to test if an array contains any elements (or is empty), you might tempted to use count to do something like this:

if (count($my_array) > 0) {
// array is not empty...

// or this ...

if (count($my_array) === 0) {
// array is empty...

Using the count function here is totally unnecessary and slower.

Instead, you should rely on the fact that empty arrays evaluate to false when cast to a boolean:

= (boolean) $my_array;

// or ...

$isEmpty = !$my_array;

// or in a conditional statement...

if ($my_array) {
// array is not empty...

Only use count if you need to know if an array contains a specific number of elements n (where n > 0).
nicolas dot grekas+php at gmail dot com
4 years ago
As of PHP 5.2.6, count() DOES detect infinite recursion.
It triggers a warning when its argument is a recursive array.
softontherocks at gmail dot com
1 year ago
I posted in my blog a small article talking about this function. If you want to visit it look at this url:
me at me dot com
2 years ago
To the poster above, the fastest way is to use 'do/while'. Try this way, you will find it faster than 'for'.
$arrayCount = count($array);
    // some code here
while($arrayCount > 0);
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