count
current() also works on objects:
<?php
echo current((object) array('one', 'two')); // Outputs: one
?>
current
(PHP 4, PHP 5)
current — Возвращает текущий элемент массива
Описание
У каждого массива имеется внутренний указатель на его "текущий" элемент, который инициализирован первым элементом, добавленным в массив.
Список параметров
-
array -
Массив.
Возвращаемые значения
Функция current() просто возвращает значение
элемента массива, на который указывает его внутренний указатель.
Она не перемещает указатель куда бы то ни было. Если
внутренний указатель находится за пределами списка элементов или
массив пуст, current() возвращает FALSE.
Внимание
Эта функция
может возвращать как boolean FALSE, так и не-boolean значение,
которое приводится к FALSE. За более подробной информацией обратитесь к разделу
Булев тип. Используйте оператор === для проверки значения,
возвращаемого этой функцией.
Примеры
Пример #1 Пример использования current() и дружественных функций
<?php
$transport = array('foot', 'bike', 'car', 'plane');
$mode = current($transport); // $mode = 'foot';
$mode = next($transport); // $mode = 'bike';
$mode = current($transport); // $mode = 'bike';
$mode = prev($transport); // $mode = 'foot';
$mode = end($transport); // $mode = 'plane';
$mode = current($transport); // $mode = 'plane';
$arr = array();
var_dump(current($arr)); // bool(false)
$arr = array(array());
var_dump(current($arr)); // array(0) { }
?>
Примечания
Замечание: Вы не сможете отличить конец массива от boolean элемента
FALSE. Для корректного обхода массива, который может содержатьFALSEэлементы, смотрите функцию each().
Смотрите также
- end() - Устанавливает внутренний указатель массива на его последний элемент
- key() - Выбирает ключ из массива
- each() - Возвращает текущую пару ключ/значение из массива и смещает его указатель
- prev() - Передвигает внутренний указатель массива на одну позицию назад
- reset() - Устанавливает внутренний указатель массива на его первый элемент
- next() - Передвигает внутренний указатель массива на одну позицию вперёд
add a note
User Contributed Notes
current
michael at squiloople dot com
10-Jan-2012 07:44
marc dot hanisch at nospam dot ateam dot de
19-May-2010 06:37
current() works with functions returning an array, too.
This is helpfull to get the first element of the returned array.
Note that current() with functions always returns the first element, because there is no variable the array was assigned to (and therefore no pointer).
Example:
<?php
//get the first element of the returned array
$element = current(get_my_arrays());
?>
In addition, current() with functions will not behave as assumed if your function returns an array reference and modifies the arrays pointer, of course!
aefxx
15-May-2008 08:39
A simple copy function that not only copies the given array but ensures the copy's pointer is set to the exact same position:
<?php
function array_copy(&array)
{
$key = key($array);
$copy = $array;
while (($copy_key = key($copy)) !== NULL) {
if ($copy_key == $key) break;
next($copy);
}
return $copy;
}
?>
That's all ... bye.
gregory at gregory dot net
27-Feb-2008 09:07
It took me a while to figure this out, but there is a more consistent way to figure out whether you really went past the end of the array, than using each().
You see, each() gets the value BEFORE advancing the pointer, and next() gets the value AFTER advancing the pointer. When you are implementing the Iterator interface, therefore, it's a real pain in the behind to use each().
And thus, I give you the solution:
To see if you've blown past the end of the array, use key($array) and see if it returns NULL. If it does, you're past the end of the array -- keys can't be null in arrays.
Nifty, huh? Here's how I implemented the Iterator interface in one of my classes:
<?php
/**
* DbRow file
* @package PalDb
*/
/**
* This class lets you use Db rows and object-relational mapping functionality.
*/
class DbRow implements Iterator
{
/**
* The DbResult object that gave us this row through fetchDbRows
* @var DbResult
*/
protected $result;
/**
* The fields of the row
* @var $fields
*/
protected $fields;
/**
* Constructor
*
* @param PDOStatement $stmt
* The PDO statement object that this result uses
* @param DbResult $result
* The result that produced this row through fetchDbRows
*/
function __construct($result)
{
$this->result = $result;
}
/**
* Get the DbResult object that gave us this row through fetchDbRows
* @return DbResult
*
* @return unknown
*/
function getResult()
{
return $this->result;
}
function __set(
$name,
$value)
{
$this->fields[$name] = $value;
}
function __get(
$name)
{
if (isset($this->fields[$name]))
return $this->fields[$name];
else
return null;
}
/**
* Iterator implementation - rewind
*/
function rewind()
{
$this->beyondLastField = false;
return reset($this->fields);
}
function valid()
{
return !$this->beyondLastField;
}
function current()
{
return current($this->fields);
}
function key()
{
return key($this->fields);
}
function next()
{
$next = next($this->fields);
$key = key($this->fields);
if (isset($key)) {
return $next[1];
} else {
$this->beyondLastField = true;
return false; // doesn't matter what we return here, see valid()
}
}
private $beyondLastField = false;
};
Hope this helps someone.
vaclav dot sir at gmail dot com
13-Aug-2007 09:23
To that "note": You won't be able to distinguish the end of an array from a boolean FALSE element, BUT you can distinguish the end from a NULL value of the key() function.
Example:
<?php
if (key($array) === null) {
echo "You are in the end of the array.";
} else {
echo "Current element: " . current($array);
}
?>
marnaq
17-Aug-2006 05:20
To make this function return a reference to the element instead, use:
<?php
function ¤t_by_ref(&$arr) {
return $arr[key($arr)];
}
?>
mdeng at kabenresearch dot com
23-Apr-2004 11:04
For large array(my sample was 80000+ elements), if you want to traverse the array in sequence, using array index $a[$i] could be very inefficient(very slow). I had to switch to use current($a).
vitalib at 012 dot net dot il
02-Dec-2003 02:10
Note that by copying an array its internal pointer is lost:
<?php
$myarray = array(0=>'a', 1=>'b', 2=>'c');
next($myarray);
print_r(current($myarray));
echo '<br>';
$a = $myarray;
print_r(current($a));
?>
Would output 'b' and then 'a' since the internal pointer wasn't copied. You can cope with that problem using references instead, like that:
<?php
$a =& $myarray;
?>
tipman
08-May-2003 04:07
if you got a array with number as index you get the last index with this:
eg:
$array[0] = "foo";
$array[1] = "foo2";
$lastKey = sizeof($array) - 1;
only a little help :)
retestro_REMOVE at SPAM_esperanto dot org dot il
01-Mar-2003 06:31
The docs do not specify this, but adding to the array using the brackets syntax:
<?php $my_array[] = $new_value; ?>
will not advance the internal pointer of the array. therefore, you cannot use current() to get the last value added or key() to get the key of the most recently added element.
You should do an end($my_array) to advance the internal pointer to the end ( as stated in one of the notes on end() ), then
<?php
$last_key = key($my_array); // will return the key
$last_value = current($my_array); // will return the value
?>
If you have no need in the key, $last_value = end($my_array) will also do the job.
- Sergey.