count

(PHP 4, PHP 5)

count — Conta o número de elementos de uma variável, ou propriedades de um objeto

Descrição

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

Conta os elementos de um array, ou propriedades em um objeto.

Para objetos, se você tem instalada, você pode fazer um gancho na count() implementando a interface Countable. A interface tem exatamente um método, count(), que retorna o valor retornado para função count().

Por favor, veja a sessão do manual para uma explicação mais detalhada sobre como os arrays são implementados e utilizados no PHP.

Parâmetros

var

The array.

mode

Se o parâmetro opcional mode for COUNT_RECURSIVE (ou 1), a função count() irá recursivamente contar a matriz. Isto é particularmente util para contar elementos em matriz multidimensional. O valor padrão para mode é 0. count() não detecta infinita recursão.

Valor Retornado

Retorna o número de elementos em var, que normalmente é um , pois qualquer outra coisa terá somente um elemento.

Se var não for um array ou um objeto, com a interface Countable implementada, 1 será retornado. Há uma exceção, se var é NULL, 0 é retornado.

Cuidado

count() pode retornar 0 para uma variável que não existe, mas também pode retornar 0 para uma variável que tenha sido inicializada como um array vazio. Use para checar se a variável existe.

Histórico

Versão Descrição
4.2.0 O parâmetro opcional mode foi adicionado.

Exemplos

Exemplo #1 Exemplo da função count()

<?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
?>

Exemplo #2 Uso recursivo da função count()

<?php
$comidas = array('frutas'  => array('laranja', 'banana', 'maçã'),
'veggie'  => array('cenoura', 'couve','ervilha'));
// contagem recursiva
echo count($comidas, COUNT_RECURSIVE);  // mostra 8
// contagem normal
echo count($comidas);                   // mostra 2
?>

Veja Também

  • - Verifica se a variável é um array
  • - Informa se a variável foi iniciada
  • - Retorna o tamanho de uma string

User Contributed Notes

gothamxi
simple random value from array.

<?php
$topic=array(
    "UFOs",
    "Barack Obama",
    "China",
    "Christianity",
    "Communism",
    "World War II",
    "Global Warming",
    "Vegetarianism",
            );

echo ("What do you think about ".$topic[ rand( 1,count($topic) ) ]."? ");

?>

output-->
What do you think about Global Warming? , etc
pro at developergatsby dot com
Complexity of count function.

I just tested the complexity of count().
It looks O(1).

Here is the result.

<< counting array with 1 element>>
total time : 0.021ms
start -> end : 100 %

<< counting array with 100000 elements>>
total time : 0.015ms
start -> end : 100 %

Here is the testing code.
mini_bench_to is a function.
<?php

$arr = array();
$arr[] = "1";

$t['start'] = microtime(true);
$size = count($arr);
$t['end'] = microtime(true);
$str_result_bench = mini_bench_to($t);
echo $str_result_bench; // string return

$arr = array();
for($index = 0; $index < 100000; $index++) {
    $arr[] = $index;
}
$t['start'] = microtime(true);
$size = count($arr);
$t['end'] = microtime(true);
$str_result_bench=mini_bench_to($t);
echo $str_result_bench; // string return

?>

<?php
function mini_bench_to($arg_t, $arg_ra=false) {
    $tttime=round((end($arg_t)-$arg_t['start'])*1000,4);
    if ($arg_ra) $ar_aff['total_time']=$tttime;
    else $aff="total time : ".$tttime."ms\n";
    $prv_cle='start';
    $prv_val=$arg_t['start'];

    foreach ($arg_t as $cle=>$val)
    {
        if($cle!='start')   
        {
            $prcnt_t=round(((round(($val-$prv_val)*1000,4)/$tttime)*100),1);
            if ($arg_ra) $ar_aff[$prv_cle.' -> '.$cle]=$prcnt_t;
            $aff.=$prv_cle.' -> '.$cle.' : '.$prcnt_t." %\n";
            $prv_val=$val;
            $prv_cle=$cle;
        }
    }
    if ($arg_ra) return $ar_aff;
    return $aff;
}
?>
marc at example dot com
Just found use for this function...
Can count an array of items where a certain condition is met.
Feel free to improve it.

function countWhere($input = 1, $operator = '==', $where = 1)
{
    $input = is_array($input) ? $input : (array)$input;
    $operator = !in_array($operator, array('<','>','<=', '>=','==', '!=')) ? '==' : $operator;

    $i = 0;

    foreach($input as $current)
    {
        $match = null;
        eval('$match = (bool)("'.$current.'"'.$operator.'"'.$where.'");');

        $i = $match ? $i+1 : $i;
    }

    return $i;
}

USAGE:
echo countWhere(array('PZ','AB','CD','EF','GH'), '!=', 'GH');

OUTPUT:
4
marc at gutt dot it
There was a change in a PHP5 version. Now an empty string returns 1:
<?php
echo count(''); // returns 1
echo count(array()); // returns 0
?>

This wasn't in PHP4 and some older PHP5 versions.
D X
To know how much properties an object has, I do it like this:
count((array) $object)
... because count($object) gives me allways 1
ravenswd at gmail dot com
The code snippet posted by legobuff at hotmail dot com on 02-Feb-2000 contains an error. This is the code that was posted:

<?php
// To find the index of the last element in the array:
end($yourArray);
$index = key($yourArray);
?>

However, this will fail if the indices have been stored out of sequence. What you actually want is max(array_keys($yourArray)), as indicated below:

<?php
$yourArray = array(1=>'a', 7=>'b', 5=>'c');

print count($yourArray); // prints 3

end($yourArray);
print key($yourArray); // prints 5

print max(array_keys($yourArray)); // prints 7
?>
jezdec at email dot cz
Hi there,
there is a simple script with example for counting rows and columns of a two-dimensional array.

<?php
$data = array(
    "apples" =>
        array("red", "yellow", "pineapples"),
    "bananas" =>
        array("small", "medium", "big"),
    "vegs" =>
        array("potatoes", "carrots", "onions")
);

$rows = count($data,0);
$cols = (count($data,1)/count($data,0))-1;
print "There are {$rows} rows and {$cols} columns in the table!";
?>
ceo at l-i-e dot com
count('') returns the very un-intuitive value of 1...
michael.debyl at gmail dot comz0r
There doesn't seem to be a succinct method already noted on this page for counting multidimensional array end nodes (Items in multidimensional arrays), so I thought this function might help somebody.

Nice and simple :)

<?php
function rcount ($array) {
  $count = 0;
  if (is_array($array)) {
    foreach($array as $id=>$sub) {
    if (!is_array($sub)) { $count++; }
     else { $count = ($count + rcount($sub)); }
    }
    return $count;
  }
  return FALSE;
}
?>
analpaper{gmail}
I found useful this little function that detects if a array is multidimensional or not.

<?php
function array_is2D($array) {
  return is_array($array) ? count($array)===count($array, COUNT_RECURSIVE) : -1;
}
?>

---
live2code
Anonymous
Here is an iterative soloution of danny's count_recursive function which might be more efficient due to the missing recursion

<?php
/**
 * counts elements of an multidimensional array
 *
 * @param array $array Input Array
 * @param int $limit dimensions that shall be considered (-1 means no limit )
 * @return int counted elements
 */
function multicount ($array, $limit = -1)
{
   $cnt = 0;
   $limit = $limit > 0 ? (int) $limit : -1;
   $arrs[] = $array;
   for ($i=0; isset($arrs[$i]) && is_array($arrs[$i]); ++$i)
   {
      foreach ($arrs[$i] as $value)
      {
         if (!is_array($value) ) ++$cnt;
         elseif( $limit==-1 || $limit>1 )
         {
            if( $limit>1 ) --$limit;
            $arrs[] = $value;
         }
      }
   }     
   return $cnt;
}
?>
atoi_monte at hotmail dot com
Please note: While SPL is compiled into PHP by default starting with PHP 5, the Countable interface is not available until 5.1
danny at dannymendel dot com
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, $limit)
{
    foreach ($array as $id => $_array)
    {
        if (is_array ($_array) && $limit > 0) $count += count_recursive ($_array, $limit - 1); else $count += 1;
    }
    return $count;
}
?>
yarolan at mail dot ru
NEVER USE IN CYCLES!

<?php
//size of $arr ~ 2000 elements

//wrong variant (Time exec ~ 19 sec)
for($i=0;$i<count($arr);$i++)
{
   //...
}

//right variant(Time exec ~ 0.2 sec)
$arr_size=count($arr);
for($i=0;$i<$arr_size;$i++)
{
   //...
}
?>

it was discovered experimentally.
Colin
<?php
// countValuesRecursive
// The goal of this function is to count non-false values of a multidimenional array
// This is useful in making a quick determination if a form sent any values
// If no values were sent I can simply return to the blank form rather than continuing to the validation of each input
// There are two limitations of the principle:
// 1. If you WANT to send FALSE, 0, '', or NULL as form values this function will not count those, thus not doing what's expected
// 2. This would create an endless loop on a form that has no required fields such as one where users can choose to recieve optional  email subscriptions but where choosing none is also valid
function countValuesRecursive($array, $count = 0) {
   
    // Cycle through the array
    foreach ($array as $value) {
       
        // Check if the value is an array
        if (is_array($value)) {
           
            // Cycle through deeper level
            $count = countValuesRecursive($value, $count);
            }
        else {
           
            // Check if the value is TRUE
            if ($value) {
                $count++;
                }
            }
        }
   
    // Return the count
    return $count;
    }
?>
alexandr at vladykin dot pp dot ru
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;
  }
?>
anil dot iitk at gmail dot com
<?php
$food = array('fruits' => array('orange', 'banana', 'apple'),
             'veggie' => array('carrot', 'collard', 'pea'));

// recursive count
echo "<br>".count($food, COUNT_RECURSIVE); // output 8

function average($a){
  return array_sum($a)/count($a) ;
}
$b = array(1,2,3,4,5,6,7,8,9);
echo "Average of array:".average($b);

?>
Scorch at netpix dot com
Be careful of recasting your variables, especially with database array returns:

<?php
$res = mysql_query("select * from blah") // a query that returns an empty set
$row = mysql_fetch_array($res); // get's 0 since there's no return
echo count($row); // echos 1 - since $row is not an array
echo $row[0]; // echos "", but casts $row as an array?
echo count($row); // echos 0 now
?>
Tom
You can find an average from an array using this and array_sum.
<?php
//array average( array input )
function average($input) {
return array_sum($input) / count($input);
}
?>

You can also do a method of form validation that involves putting all errors into an array and letting count() do the key part.
<?php
if(isset($_POST['submit'])) {
$errors = array();
if(empty($_POST['message'])) $errors[] = "Empty message field";
if(!preg_match('/[a-z0-9.]@[a-z0-9].[a-z]/i', $_POST['email']) {
$errors[] = "Bad email address";
  }
if(count($errors) == 0) {
//process form...
  }
}
?>
Fred D
The trim_text function was helpful, but it did not take account of the possibility of having nothing to trim which can sometimes happen if you are using this function in a loop through data. I've added a count function to deal with that possibility

<?php
function trim_text_elipse($text, $count){
//Create variable
$trimmed="";

//Remove double white space
$text = str_replace("  ", " ", $text);

//Turn the text into an array
$string = explode(" ", $text);

//Check to see how many words there are
$wordTotal = count($string);   
    //Check to see if there are more words than the $count variable
    if($wordTotal > $count){
        //Loop through adding words until the $count variable is reached
        for ( $wordCounter = 0; $wordCounter <= $count; $wordCounter++ ){
            $trimmed .= $string[$wordCounter];
                //Check to and add space or finish with elipse           
                if ( $wordCounter < $count ){ $trimmed .= " "; }
                else { $trimmed .= " &#8230;"; }
                }
    }else{
    //Set value returned to the existing value
    $trimmed =$text;
    }
//Trim off any white space   
$trimmed = trim($trimmed);
return $trimmed;
}

?>
david _at_ webgroup _dot_ org
While michael at htmlland dot net's code works, I believe it is better to use:
$extension=substr($file,strrpos($file,".")+1);

This doesn't incur the overhead of array handling.  I haven't tested it for time functions, but it should work just as well and SHOULD be faster.
freefaler at gmail dot com
If you want to count only elements in the second level of 2D arrays.A close to mind note, useful for multidimentional arrays:

<?php
$food = 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
?>
moazzam at ummah dot org
This is an obvious note, but I am writing it any way so other, who did may not have observed this, can take advantage of it too.

When running loops with count conditions, the code runs faster if you first assign the count() value to a variable and use that (instead of using count() directly in a loop condition.

To explain my point better, here is an example:

<?php

for ($i=0; $i<10000; $i++) {
    $arr[] = $i;
}

$time11 = microtime_float();
$bf = "";
for ($i=0; $i<count($arr); $i++) {
    $bf .= $arr[$i]."\n";
}
$time12 = microtime_float();
$time1 = $time12 - $time11;

print "First: ".$time1."\n";

$time21 = microtime_float();
$l = count($arr);
for ($i=0; $i<$l; $i++) {
    $bf .= $arr[$i]."\n";
}
$time22 = microtime_float();
$time2 = $time22 - $time21;

print "Second: ".$time2."\n";

?>

The output from the code above is (when run many times):

First: 0.13001585006714
Second: 0.099159002304077

First: 0.12128901481628
Second: 0.079941987991333

First: 0.18690299987793
Second: 0.13346600532532

As you can see, the second method (which doesnt use count() directly in the loop) is faster than the first method (which uses count() directly in the loop).

BTW:  I copied the microtime_float() function from one of the comments in the microtime() section. It just returns time with microseconds as float. Check comments in microtime() for more info.
michael at htmlland dot net
I have found on upload scripts or on file manipulation scripts that people can trick a classic file type filter:
example:

<?php
$filename="bob.jpg.wav";
$bits= explode(".",$filename);
$extention= $bits[1];
if($extention == "jpg"){ echo"Not correct"; exit; }
?>

This returns the filename extention as jpg not wav.

One way to change this is to use count() :
example:

<?php
$filename="bob.jpg.wav";
$bits= explode(".",$filename);
$extention= $bits[count($bits) - 1];
if($extention == "jpg"){ echo "Not correct"; exit; }
?>

This returns the filename extention as wav not jpg.
rolandfoxx at yahoo dot com
As an addition, any of the array manipulation functions can likewise get count to once again return 0:

<?php
$a = array();
print(count($a)); // prints 0
$a[0] = "foo";
array_shift($a);
print(count($a)); //prints 0
$a[0] = "bar";
array_splice($a, 0, 1);
print(count($a)); //prints 0
?>
admin at lft-muenchen dot de
Note:

<?php
print (strlen($a)); // will print 0
$a="";
print (strlen($a)); // will print 1
$a=null;
print (strlen($a)); // will print 1
$a=array();
print (strlen($a)); // will print 0
?>

you can only get an array back to size 0 by using the array() command, not by just setting it to "" or null.
simon at invalid dot com
Reminder for using count():

<?php
$ary = array(null, "a", "b", null);
echo count($ary);    // count: 4

$ary[10] = "c";
echo count($ary);    // count: 5

$ary[15] = null;
echo count($ary);    // count: 6
?>

=> NULL is seen as an element in count()

Count 2D array:

<?php
$a2Dary = array(array("a", "b") , array(), "v");

echo count($a2Dary);        // count: 3
echo count($a2Dary[0]);    //count 2
echo count($a2Dary[1]);    // count: 0
echo count($a2Dary[2]);    // count: 1
?>

Hope can help you
webmaster at NOSPAMtrafficg dot com
Counting a multi-dimentional array

test array

<?php
$settings[0][0]  = 128;
$settings[0][1]  = 256;
$settings[0][2]  = 384;
$settings[0][3]  = 512;
$settings[0][4]  = 1024;
$settings[0][5]  = 2048;

$settings[1][0]  = 1024;
$settings[1][1]  = 2048;
$settings[1][2]  = 3072;
$settings[1][3]  = 4096;

count($settings) // returns 2
count($settings[0]) // returns 6
count($settings[1]) // returns 4
?>
kanareykin at denison dot edu
Here's how to count non-empty elements
in an array of any dimension. Hope
it will be useful for somebody.

<?php
// recursively count all non-empty elements
// in array of any dimension or mixed - i.e.
// array('1' => 2, '2' => array('1' => 3, '2' => 4))
function count_all($arg)
{
    // skip if argument is empty
    if ($arg)    {
        // not an array, return 1 (base case)
        if(!is_array($arg))
            return 1;
        // else call recursively for all elements $arg
        foreach($arg as $key => $val)
            $count += count_all($val);
           
        return $count;       
    }
}
?>
martin at complinet dot com
The count function does not ignore null values in an array. To achieve this use this function.

<?php
function xcount($array) {
        while (list($key, $value) = each($array)) {
                if ($value) {
                        $count++;
                }
        }
return $count;
}
?>
jmcastagnetto at php dot net
If you want to disambiguate if a variable contains an array w/ only one element, just us is_array() or gettype()
legobuff at hotmail dot com
This is taken from sganer@expio.co.nz comments on the sizeof() function:
If some elements in your array are not set, then sizeof() and count() will not return the index of the last element, but will return the number of set elements. To find the index of the last element in the array:

end($yourArray);
$index = key($yourArray);

... Where $yourArray is the array you want to find the last index ($index) of.