Use php to count

Use php to count

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Источник

PHP count() Function

The count() function returns the number of elements in an array.

Syntax

Parameter Values

• 0 — Default. Does not count all elements of multidimensional arrays
• 1 — Counts the array recursively (counts all the elements of multidimensional arrays)

Technical Details

Return Value:	Returns the number of elements in the array
PHP Version:	4+
PHP Changelog:	The mode parameter was added in PHP 4.2

More Examples

Example

Count the array recursively:

echo «Normal count: » . count($cars).»
«;
echo «Recursive count: » . count($cars,1);
?>

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Источник

count

Counts all elements in an array when used with an array. When used with an object that implements the Countable interface, it returns the return value of the method Countable::count() .

Parameters

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.

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 value . Prior to PHP 8.0.0, if the parameter was neither an array nor an object that implements the Countable interface, 1 would be returned, unless value was null , in which case 0 would be returned.

Changelog

Version	Description
8.0.0	count() will now throw TypeError on invalid countable types passed to the value parameter.
7.2.0	count() will now yield a warning on invalid countable types passed to the value parameter.

Examples

Example #1 count() example

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

$b [ 0 ] = 7 ;
$b [ 5 ] = 9 ;
$b [ 10 ] = 11 ;
var_dump ( count ( $b ));
?>

The above example will output:

Example #2 count() non Countable|array example (bad example — don’t do this)

$b [ 0 ] = 7 ;
$b [ 5 ] = 9 ;
$b [ 10 ] = 11 ;
var_dump ( count ( $b ));

The above example will output:

Output of the above example in PHP 7.2:

int(3) Warning: count(): Parameter must be an array or an object that implements Countable in … on line 12 int(0) Warning: count(): Parameter must be an array or an object that implements Countable in … on line 14 int(1)

Output of the above example in PHP 8:

int(3) Fatal error: Uncaught TypeError: count(): Argument #1 ($var) must be of type Countable .. on line 12

Example #3 Recursive count() example

$food = array( ‘fruits’ => array( ‘orange’ , ‘banana’ , ‘apple’ ),
‘veggie’ => array( ‘carrot’ , ‘collard’ , ‘pea’ ));

// recursive count
var_dump ( count ( $food , COUNT_RECURSIVE ));

// normal count
var_dump ( count ( $food ));

The above example will output:

Example #4 Countable object

class CountOfMethods implements Countable
private function someMethod ()
>

public function count (): int
return count ( get_class_methods ( $this ));
>
>

$obj = new CountOfMethods ();
var_dump ( count ( $obj ));
?>

The above example will output:

See Also

• is_array() — Finds whether a variable is an array
• isset() — Determine if a variable is declared and is different than null
• empty() — Determine whether a variable is empty
• strlen() — Get string length
• is_countable() — Verify that the contents of a variable is a countable value
• Arrays

• Array Functions
  • array_​change_​key_​case
  • array_​chunk
  • array_​column
  • array_​combine
  • array_​count_​values
  • array_​diff_​assoc
  • array_​diff_​key
  • array_​diff_​uassoc
  • array_​diff_​ukey
  • array_​diff
  • array_​fill_​keys
  • array_​fill
  • array_​filter
  • array_​flip
  • array_​intersect_​assoc
  • array_​intersect_​key
  • array_​intersect_​uassoc
  • array_​intersect_​ukey
  • array_​intersect
  • array_​is_​list
  • array_​key_​exists
  • array_​key_​first
  • array_​key_​last
  • array_​keys
  • array_​map
  • array_​merge_​recursive
  • array_​merge
  • array_​multisort
  • array_​pad
  • array_​pop
  • array_​product
  • array_​push
  • array_​rand
  • array_​reduce
  • array_​replace_​recursive
  • array_​replace
  • array_​reverse
  • array_​search
  • array_​shift
  • array_​slice
  • array_​splice
  • array_​sum
  • array_​udiff_​assoc
  • array_​udiff_​uassoc
  • array_​udiff
  • array_​uintersect_​assoc
  • array_​uintersect_​uassoc
  • array_​uintersect
  • array_​unique
  • array_​unshift
  • array_​values
  • array_​walk_​recursive
  • array_​walk
  • array
  • arsort
  • asort
  • compact
  • count
  • current
  • end
  • extract
  • in_​array
  • key_​exists
  • key
  • krsort
  • ksort
  • list
  • natcasesort
  • natsort
  • next
  • pos
  • prev
  • range
  • reset
  • rsort
  • shuffle
  • sizeof
  • sort
  • uasort
  • uksort
  • usort
  • each

  Источник

  count

  Подсчитывает количество элементов массива или что-то в объекте.

  Для объектов, если у вас включена поддержка SPL, вы можете перехватить count() , реализуя интерфейс Countable. Этот интерфейс имеет ровно один метод, Countable::count() , который возвращает значение функции count() .

  Пожалуйста, смотрите раздел «Массивы» в этом руководстве для более детального представления о реализации и использовании массивов в PHP.

  Список параметров

  Если необязательный параметр mode установлен в COUNT_RECURSIVE (или 1), count() будет рекурсивно подсчитывать количество элементов массива. Это особенно полезно для подсчёта всех элементов многомерных массивов.

  count() умеет определять рекурсию для избежания бесконечного цикла, но при каждом обнаружении выводит ошибку уровня E_WARNING (в случае, если массив содержит себя более одного раза) и возвращает большее количество, чем могло бы ожидаться.

  Возвращаемые значения

  Возвращает количество элементов в array_or_countable . Если параметр не является массивом или объектом, реализующим интерфейс Countable, будет возвращена 1. За одним исключением: если array_or_countable — NULL , то будет возвращён 0.

  count() может возвратить 0 для переменных, которые не установлены, но также может возвратить 0 для переменных, которые инициализированы пустым массивом. Используйте функцию isset() для того, чтобы протестировать, установлена ли переменная.

  Примеры

  Пример #1 Пример использования count()

  $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
  ?>

  Пример #2 Пример рекурсивного использования count()

  $food = array( ‘fruits’ => array( ‘orange’ , ‘banana’ , ‘apple’ ),
  ‘veggie’ => array( ‘carrot’ , ‘collard’ , ‘pea’ ));

  // рекурсивный count
  echo count ( $food , COUNT_RECURSIVE ); // выводит 8

  // обычный count
  echo count ( $food ); // выводит 2

  Смотрите также

  • is_array() — Определяет, является ли переменная массивом
  • isset() — Определяет, была ли установлена переменная значением отличным от NULL
  • strlen() — Возвращает длину строки

  Источник