International PHP Conference 2015

count

(PHP 4, PHP 5)

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

Descrierea

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.

Parametri

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.

Precauţie

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.

Valorile întoarse

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.

Precauţie

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.

Exemple

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

?>

A se vedea și

  • is_array() - Determină dacă o variabilă este un array
  • isset() - Determină dacă o variablă este stabilită și nu este NULL
  • strlen() - Get string length

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