current

(PHP 4, PHP 5, PHP 7, PHP 8)

current — 配列内の現在の要素を返す

説明

current(array|object $array): mixed

各配列は、"カレント"の要素へのポインタを有しています。このポインタは、配列に挿入された最初の要素を指すように初期化されます。

パラメータ

array: 配列。

戻り値

current() 関数は、単に内部ポインタが現在指している配列要素の値を返します。この関数は、ポインタを全く移動しません。内部ポインタが最終要素の次を指していたり配列が空だったりした場合、 current() は false を返します。

警告

この関数は論理値 false を返す可能性がありますが、false として評価される値を返す可能性もあります。詳細については論理値のセクションを参照してください。この関数の返り値を調べるには ===演算子を使用してください。

変更履歴

バージョン	説明
8.1.0	この関数を object に対してコールすることは、推奨されなくなりました。 object に対して最初に get_mangled_object_vars() を使って配列に変換するか、ArrayIterator のような Iterator を実装したクラスのメソッドを使ってください。
7.4.0	SPL クラスのインスタンスは、プロパティを持たない空のオブジェクトのように扱われるようになりました。これより前のバージョンでは、この関数と同じ名前の Iterator のメソッドをコールしていました。

例

例1 current() と類似関数の使用例

<?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) { }
?>

注意

注意: 配列の最終要素の次を指していた場合や、空の配列に対して、current() を呼び出した時の結果は、 bool false 要素を指していた場合と区別できません。 false 要素を含む配列を順に処理するには、制御構文 foreach を参照ください。それでも current() を使い、値が本当に配列の要素であることを適切にチェックするには、 current() が指す要素の key() の値が、厳密に null ではないことをチェックすべきです。

参考

end() - 配列の内部ポインタを最終要素にセットする
key() - 配列からキーを取り出す
each() - 配列から現在のキーと値のペアを返して、カーソルを進める
prev() - 内部の配列ポインタをひとつ前に戻す
reset() - 配列の内部ポインタを先頭の要素にセットする
next() - 配列の内部ポインタを進める
foreach

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User Contributed Notes 13 notes

down

sergey dot karavay at gmail dot com ¶

3 years ago

It looks like `current()` is deprectated for calling on objects since PHP 7.4. 

Consider this code

```
$a = new ArrayIterator([1,2,3]);

var_dump(current($a), $a->current());
```

It returns 
```
int(1)
int(1)
```

In PHP 7.3, but in PHP7.4 you get:
```
bool(false)
int(1)
```

And in PHP8:
```
Deprecated: current(): Calling current() on an object is deprecated in /in/fdrNR on line 5
bool(false)
int(1)
```

down

michael at squiloople dot com ¶

12 years ago

current() also works on objects:



<?php



  echo current((object) array('one', 'two')); // Outputs: one



?>

down

strate at yandex dot com ¶

11 years ago

Note, that you can pass array by expression, not only by reference (as described in doc).

<?php
var_dump( current( array(1,2,3) ) ); // (int) 1
?>

down

vaclav dot sir at gmail dot com ¶

17 years ago

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);
}
?>

down

retestro_REMOVE at SPAM_esperanto dot org dot il ¶

21 years ago

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.

down

mdeng at kabenresearch dot com ¶

20 years ago

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).

down

Vasily Yudin (st-2 at mail dot ru) ¶

10 years ago

If you do current() after using uset() on foreach statement, you can get FALSE in PHP version 5.2.4 and above.
There is example:
<?php
$prices = array(
    0 => '1300990',
    1 => '500',
    2 => '600'
);
foreach($prices as $key => $price){
    if($price < 1000){
        unset($prices[$key]);
    }
}

var_dump(current($prices)); // bool(false)
?>
If you do unset() without foreach? all will be fine.
<?php
$prices = array(
    0 => '1300990',
    1 => '500',
    2 => '600'
);
unset($prices[1]);
unset($prices[2]);

var_dump(current($prices));
?>

down

leozmm at outlook dot com ¶

5 years ago

Array can be passed by both REFERENCE and EXPRESSION on `current`, because current doesn't move array's internal pointer,
this is not true for other functions like: `end`, `next`, `prev` etc.

<?php
    function foo() {return array(1,2,3);}
    echo current(foo());  // this print '1'
    echo end(foo());      // this print error: Only variables should be passed by reference
?>

down

xedin dot unknown at gmail dot com ¶

6 years ago

Array functions, such as `current()` and `rewind()` will work on `Traversable` as well, PHP 5.0 - 7.3, but not in HHVM:

<?php

$queue = new ArrayIterator(array('adasdasd'));
reset($queue);
$current = current($queue);
var_dump($current);

?>

See https://3v4l.org/VjCHR

down

vitalib at 012 dot net dot il ¶

20 years ago

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;
?>

down

pdarmis at gmail dot com ¶

7 years ago

Based on this example http://php.net/manual/en/function.current.php#116128 i would like to add the following.  As Vasily points out in his example 
<?php
$prices = array(
    0 => '1300990',
    1 => '500',
    2 => '600'
);
foreach($prices as $key => $price){
    if($price < 1000){
        unset($prices[$key]);
    }
}

var_dump(current($prices)); // bool(false)
?>
The above example will not work and return false for version of PHP between 5.2.4 and 5.6.29. The issue is not present on PHP versions >= 7.0.1
A different workaround (at least from Vasily's example) would be to use reset() before using current() in order to reset the array pointer to start.
<?php
$prices = array(
    0 => '1300990',
    1 => '500',
    2 => '600'
);
foreach($prices as $key => $price){
    if($price < 1000){
        unset($prices[$key]);
    }
}
reset($prices);
var_dump(current($prices)); // string(7) "1300990"
?>

down

gregory at gregory dot net ¶

16 years ago

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.

down

-4

Pratip Ghosh ¶

10 years ago

If we unset any element from an array, and then try the current function, I noted it returned FALSE. To overcome this limitation, you can use array_values function to re-order the tree.

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