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countConta gli elementi in una variabile, o le proprietà in un oggetto


int count ( mixed $var [, int $mode ] )

Restituisce il numero di elementi in var, la quale è di norma un array, dal momento che qualsiasi altro oggetto avrà un elemento.

Per gli oggetti, se SPL è installato, è possibile agganciarsi a count() implementando l'interfaccia Countable. L'interfaccia ha esattamente un metodo, count(), che ritorna il valore restituito dalla funzione count().

Se var non è un array o un oggetto con l'interfaccia Countable implementata, verrà restituito 1 C'è una eccezione, se var è NULL, verrà restituito 0.

Nota: Il parametro opzionale mode è disponibile da PHP 4.2.0.

Se il parametro opzionale mode è impostato a COUNT_RECURSIVE (o 1), count() conterà ricorsivamente l'array. Questo è utile in particolare per contare tutti gli elementi di un array multidimensionale. Il valore di default per mode è 0. count() non identifica le ricorsioni infinite.


count() può restituire 0 per una variabile che non è impostata, ma può anche restituire 0 per una variabile che è stata inizializzata con un array vuoto. Usare isset() per verificare se una variabile è impostata.

Vedere la sezione Array nel manuale per una spiegazione dettagliata di come gli array siano implementati ed usati in PHP.

Example #1 esempio di count()

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

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

$result count(null);
// $result == 0

$result count(false);
// $result == 1

Example #2 esempio di count() ricorsiva (PHP >= 4.2.0)

= array('frutta' => array('arancia''banana''mela'),
'verdura' => array('carota''zucchina''piselli'));

// conteggio ricorsivo
echo count($cibp,COUNT_RECURSIVE); // output 8

// conteggio normale
echo count($cibo);                 // output 2


Vedere anche is_array(), isset() e strlen().

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User Contributed Notes 16 notes

onlyranga at gmail dot com
9 months 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
alexandr at vladykin dot pp dot ru
8 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);
danny at dannymendel dot com
7 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;
Gerd Christian Kunze
1 year 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? ;-)
jingsoft at 126 dot com
1 month ago
There is an array:
$array = array ( 1, array( 1, 2, 3));
use count($array) will return 5, is a bug?
array at from dot pl
7 days 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: https://nikic.github.io/2012/03/28/Understanding-PHPs-internal-array-implementation.html

[1] https://github.com/php/php-src/blob/PHP-5.5/ext/standard/array.c#L306
[2] https://github.com/php/php-src/blob/e10e151e9b92313a7085272c85bebf6c82017fce/ext/standard/array.c#L264
atoi_monte at hotmail dot com
7 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
1 year 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!
jezdec at email dot cz
5 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!";
lopezvit at gmail dot com
1 year 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.
MaxTheDragon at home dot nl
1 year 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).
freefaler at gmail dot com
10 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
nicolas dot grekas+php at gmail dot com
3 years ago
As of PHP 5.2.6, count() DOES detect infinite recursion.
It triggers a warning when its argument is a recursive array.
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;
softontherocks at gmail dot com
3 months 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
1 year 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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