count

(PHP 4, PHP 5)

countCount all elements in an array, or something in an object

Description

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

Counts all elements in an array, or something in an object.

For objects, if you have SPL installed, you can hook into count() by implementing interface Countable. The interface has exactly one method, Countable::count(), which returns the return value for the count() function.

Please see the Array section of the manual for a detailed explanation of how arrays are implemented and used in PHP.

Parameters

array_or_countable

An array or Countable object.

mode

If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array.

Caution

count() can detect recursion to avoid an infinite loop, but will emit an E_WARNING every time it does (in case the array contains itself more than once) and return a count higher than may be expected.

Return Values

Returns the number of elements in array_or_countable. If the parameter is not an array or not an object with implemented Countable interface, 1 will be returned. There is one exception, if array_or_countable is NULL, 0 will be returned.

Caution

count() may return 0 for a variable that isn't set, but it may also return 0 for a variable that has been initialized with an empty array. Use isset() to test if a variable is set.

Changelog

Version Description
4.2.0 The optional mode parameter was added.

Examples

Example #1 count() example

<?php
$a
[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
?>

Example #2 Recursive count() example

<?php
$food 
= array('fruits' => array('orange''banana''apple'),
              
'veggie' => array('carrot''collard''pea'));

// recursive count
echo count($foodCOUNT_RECURSIVE); // output 8

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

?>

See Also

  • is_array() - Finds whether a variable is an array
  • isset() - Determine if a variable is set and is not NULL
  • strlen() - Get string length

Коментарии

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).

<?php
 
function getArrCount ($arr$depth=1) {
      if (!
is_array($arr) || !$depth) return 0;
         
     
$res=count($arr);
         
      foreach (
$arr as $in_ar)
         
$res+=getArrCount($in_ar$depth-1);
     
      return 
$res;
  }
?>
2006-11-08 06:28:14
http://php5.kiev.ua/manual/ru/function.count.html
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.

// $limit is set to the number of recursions
<?php
function count_recursive ($array$limit) {
   
$count 0;
    foreach (
$array as $id => $_array) {
        if (
is_array ($_array) && $limit 0) {
           
$count += count_recursive ($_array$limit 1);
        } else {
           
$count += 1;
        }
    }
    return 
$count;
}
?>
2007-06-13 16:14:43
http://php5.kiev.ua/manual/ru/function.count.html
Get maxWidth and maxHeight of a two dimensional array..?

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

<?php
$TwoDimensionalArray 
= array( => array( 'key' => 'value', ...), ... );
?>

So for Y (maxHeight) 
<?php
$maxHeight 
count$TwoDimensionalArray )
?>

And for X (maxWidth)
<?php
$maxWidth 
maxarray_map'count'$TwoDimensionalArray ) );
?>

Simple? ;-)
2013-12-11 14:56:19
http://php5.kiev.ua/manual/ru/function.count.html
[Editor's note: array at from dot pl had pointed out that count() is a cheap operation; however, there's still the function call overhead.]

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.

Eg:

// Bad approach

for($i=0;$i<count($some_arr);$i++)
{
    // calculations
}

// Good approach

$arr_length = count($some_arr);
for($i=0;$i<$arr_length;$i++)
{
    // calculations
}
2014-04-28 05:14:32
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
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.
e.g.
<?php
    $array 
= [15'element'];
    for(
$i 0$c count($array); $i $c$i++)
       
var_dump($array[$i]);
?>
2015-05-05 17:18:43
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
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;
}
2015-06-04 20:27:30
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
About 2d arrays, you have many way to count elements :

<?php
$MyArray 
= array ( array(1,2,3),
                   
1,
                   
'a',
                   array(
'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))
?>
2015-12-17 17:10:49
http://php5.kiev.ua/manual/ru/function.count.html
All the previous recursive count solutions with $depth option would not avoid infinite loops in case the array contains itself more than once.
Here's a working solution:

<?php
   
/**
     * Recursively count elements in an array. Behaves exactly the same as native
     * count() function with the $depth option. Meaning it will also add +1 to the
     * total count, for the parent element, and not only counting its children.
     * @param $arr
     * @param int $depth
     * @param int $i (internal)
     * @return int
     */
   
public static function countRecursive(&$arr$depth 0$i 0) {
       
$i++;
       
/**
         * In case the depth is 0, use the native count function
         */
       
if (empty($depth)) {
            return 
count($arrCOUNT_RECURSIVE);
        }
       
$count 0;
       
/**
         * This can occur only the first time when the method is called and $arr is not an array
         */
       
if (!is_array($arr)) {
            return 
count($arr);
        }

       
// if this key is present, it means you already walked this array
       
if (isset($arr['__been_here'])) {
            return 
0;
        }

       
$arr['__been_here'] = true;

        foreach (
$arr as $key => &$value) {
            if (
$key !== '__been_here') {
                if (
is_array($value) && $depth $i) {
                   
$count += self::countRecursive($value$depth$i);
                }

               
$count++;
            }
        }

       
// you need to unset it when done because you're working with a reference...
       
unset($arr['__been_here']);
        return 
$count;
    }
?>
2016-11-22 17:12:41
http://php5.kiev.ua/manual/ru/function.count.html
You can not get collect sub array count when there is only one sub array in an array: 

$a = array ( array ('a','b','c','d'));
$b = array ( array ('a','b','c','d'), array ('e','f','g','h'));

echo count($a);  // 4 NOT 1, expect 1
echo count($b);  // 2,   expected
2017-01-27 00:32:35
http://php5.kiev.ua/manual/ru/function.count.html
You can not get collect sub array count when use the key on only one sub array in an array: 

$a = array("a"=>"appple", b"=>array('a'=>array(1,2,3),'b'=>array(1,2,3)));
$b = array("a"=>"appple", "b"=>array(array('a'=>array(1,2,3),'b'=>array(1,2,3)), array(1,2,3),'b'=>array(1,2,3)), array('a'=>array(1,2,3),'b'=>array(1,2,3))));

echo count($a['b']);  // 2 NOT 1, expect 1
echo count($b['b']);  // 3,   expected
2017-01-27 23:16:10
http://php5.kiev.ua/manual/ru/function.count.html
If you are on PHP 7.2+, you need to be aware of "Changelog" and use something like this:

<?php
$countFruits 
is_array($countFruits) || $countFruits instanceof Countable count($countFruits) : 0;
?>

You can organize your code to ensure that the variable is an array, or you can extend the Countable so that you don't have to do this check.
2019-03-08 01:26:35
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
For a Non Countable Objects

$count = count($data);
print "Count: $count\n";

Warning:  count(): Parameter must be an array or an object that implements Countable in example.php on line 159

#Quick fix is to just cast the non-countable object as an array.. 

$count = count((array) $data);
print "Count: $count\n";

Count: 250
2019-10-05 08:52:20
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
If you want to know the sub-array containing the MAX NUMBER of values in a 3 dimensions array, here is a try (maybe not the nicest way, but it works):

function how_big_is_the_biggest_sub ($array)  {
   // we parse the 1st level
   foreach ($array AS $key => $array_lvl2) {
         //within level 2, we count the 3d levels max
            $lvl2_nb = array_map( 'count',  $array_lvl2) ;
            $max_nb = max($lvl2_nb);
         // we store the matching keys, it might be usefull
            $max_key = array_search($max_nb, $lvl2_nb);
            $max_nb_all[$max_key.'|'.$key] = $max_nb;
        }
       // now we want the max from all levels 2, so one more time
        $real_max = max($max_nb_all);
        $real_max_key = array_search($real_max, $max_nb_all);
        list($real_max_key2, $real_max_key1) = explode('|', $real_max_key);
                // preparing result
        $biggest_sub['max'] = $real_max;
        $biggest_sub['key1'] = $real_max_key1;
        $biggest_sub['key2'] = $real_max_key2;
       
        return $biggest_sub;
}
/*
$cat_poids_max['M']['Juniors'][] = 55; 
$cat_poids_max['M']['Juniors'][] = 61; 
$cat_poids_max['M']['Juniors'][] = 68; 
$cat_poids_max['M']['Juniors'][] = 76; 
$cat_poids_max['M']['Juniors'][] = 100; 

$cat_poids_max['M']['Seniors'][] = 55; 
$cat_poids_max['M']['Seniors'][] = 60; 
$cat_poids_max['M']['Seniors'][] = 67; 
$cat_poids_max['M']['Seniors'][] = 75; 
$cat_poids_max['M']['Seniors'][] = 84; 
$cat_poids_max['M']['Seniors'][] = 90; 
$cat_poids_max['M']['Seniors'][] = 100; 
//....
$cat_poids_max['F']['Juniors'][] = 52; 
$cat_poids_max['F']['Juniors'][] = 65; 
$cat_poids_max['F']['Juniors'][] = 74; 
$cat_poids_max['F']['Juniors'][] = 100; 

$cat_poids_max['F']['Seniors'][] = 62; 
$cat_poids_max['F']['Seniors'][] = 67; 
$cat_poids_max['F']['Seniors'][] = 78; 
$cat_poids_max['F']['Seniors'][] = 86; 
$cat_poids_max['F']['Seniors'][] = 100; 
*/
$biggest_sub = how_big_is_the_biggest_sub($cat_poids_max);
echo "<li> ".$biggest_sub['key1']." ==> ".$biggest_sub['key2']." ==> ".$biggest_sub['max']; // displays : M ==> Seniors ==> 7
2020-01-31 00:59:01
http://php5.kiev.ua/manual/ru/function.count.html
In special situations you might only want to count the first level of the array to figure out how many entries you have, when they have N more key-value-pairs.

<?php

$data 
= [
   
'a' => [
       
'bla1' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ],
       
'bla2' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ],
       
'bla3' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ],
       
'bla4' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ],
    ],
   
'b' => [
       
'bla1' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ],
       
'bla2' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ],
    ],
   
'c' => [
       
'bla1' => [
           
=> 'asdf',
           
=> 'asdf',
           
=> 'asdf',
        ]
    ]
];
$count array_sum(array_values(array_map('count'$data)));
// will return int(7)
var_dump($count);

// will return 31
var_dump(count($data1));
?>
2020-03-08 02:12:29
http://php5.kiev.ua/manual/ru/function.count.html
To get the count of the inner array you can do something like:

$inner_count = count($array[0]);
echo ($inner_count);
2020-06-25 15:29:14
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
Empty values are counted:
<?php
$ar
[] = 3;
$ar[] = null;
var_dump(count($ar)); //int(2)
?>
2021-12-25 14:04:12
http://php5.kiev.ua/manual/ru/function.count.html
Автор:
count and sizeof are aliases, what work for one works for the other.
2022-03-14 17:03:14
http://php5.kiev.ua/manual/ru/function.count.html
In example #3, given as:

<?php
$food 
= array('fruits' => array('orange''banana''apple'),
             
'veggie' => array('carrot''collard''pea'));

// recursive count
var_dump(count($foodCOUNT_RECURSIVE));
?>

with the output given as int(8), it may have some readers mistaken, as I was at first: one might take it as keys being counted as well as the inner array entries:

<?php
// NO:
'fruits''orange''banana''apple'
'veggie''carrot''collard''pea'
?>

But actually keys are not counted in count function, and why it is still 8 - because inner arrays are counted as entries as well as their inner elements:

<?php
// YES:
array('orange''banana''apple'), 'orange''banana''apple'
array(
'carrot''collard''pea'), 'carrot''collard''pea'
?>
2023-05-28 16:08:12
http://php5.kiev.ua/manual/ru/function.count.html

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