next

(PHP 4, PHP 5, PHP 7)

next배열의 내부 배열 포인터를 전진

설명

mixed next ( array &$array )

next()current()와 비슷하게 동작하지만 한가지 차이를 갖고 있다. 원소값을 반환하기 전에 내부 배열 포인터를 한칸 다음으로 전진시킨다. 이 말은 다음 배열 값을 반환하고 내부 배열 포인터를 한칸 전진시킨다는 뜻이다.

인수

array

영향 받는 array

반환값

내부 배열 포인터가 가리키는 다음 위치의 배열 값을 반환하거나, 더 이상 원소가 없을 경우에는 FALSE를 반환합니다.

Warning

이 함수는 논리 FALSE를 반환하지만, 논리 FALSE로 취급할 수 있는 다른 값을 반환할 수 있습니다. 자세한 정보는 논리형 섹션을 참고하십시오. 이 함수의 반환값을 확인하려면 === 연산자를 이용하십시오.

예제

Example #1 next()의 용례와 관련 함수

<?php
$transport 
= array('foot''bike''car''plane');
$mode current($transport); // $mode = 'foot';
$mode next($transport);    // $mode = 'bike';
$mode next($transport);    // $mode = 'car';
$mode prev($transport);    // $mode = 'bike';
$mode end($transport);     // $mode = 'plane';
?>

주의

Note: 배열의 끝과 boolean FALSE 원소를 구별할 수 없습니다. FALSE 원소를 가지는 배열을 올바르게 따라가려면, each()를 참고하십시오.

  • current() - 배열의 현재 원소를 반환
  • end() - 배열 내부 포인터가 마지막 원소를 가리키게 설정
  • prev() - 내부 배열 포인터를 후진
  • reset() - 배열의 내부 포인터를 첫 원소로 설정
  • each() - 배열에서 현재 키와 값 쌍을 반환하고 배열 커서를 전진

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User Contributed Notes 15 notes

up
15
JumpIfBelow
2 years ago
Now from PHP 7.2, the function "each" is deprecated, so the has_next I've posted is no longer a good idea. There is another to keep it simple and fast:

<?php
function has_next(array $_array)
{
  return
next($_array) !== false ?: key($_array) !== null;
}
?>
up
5
brentimus
14 years ago
Papipo's function below is usefull in concept but does not work.

"Since you do not pass the array by reference, its pointer is only moved inside the function."

This is true, but the array you are manipulating in your has_next() function will have it's pointer set to the first element, not the same position as the original array. What you want to do is pass the array to the has_next() function via reference. While in the has_next() function, make a copy of the array to work on. Find out the current pointer position of the original array and set the pointer on the working copy of the array to the same element. Then you may test to see if the array has a "next" element.

Try the followig insetad:

<?php
function has_next(&$array)
{
   
$A_work=$array//$A_work is a copy of $array but with its internal pointer set to the first element.
   
$PTR=current($array);
   
array_set_pointer($A_work, $PTR);

    if(
is_array($A_work))
    {
        if(
next($A_work)===false)
            return
false;
        else
            return
true;
    }
    else
        return
false;
}

function
array_set_pointer(&$array, $value)
{
   
reset($array);
    while(
$val=current($array))
    {
        if(
$val==$value)
            break;

       
next($array);
    }
}
?>
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3
gg2005 at gmail dot com
12 years ago
Don't confuse next with continue!

If you're a Perl developer starting with PHP, you might try to use "next" inside a loop to skip to the next iteration...  

i.e.,

foreach ($things as $thing) {
  if (something I don't like about $thing) {
   next;
  }
  blah....
}

The php compiler will take next... but it's not going to work.

Do this instead:
foreach ($things as $thing) {
  if (something I don't like about $thing) {
   continue;
  }
  blah....
}
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4
papipo's gmail account
14 years ago
I need to know if an array has more items, but without moving array's internail pointer. Thats is, a has_next() function:

<?php
function has_next($array) {
    if (
is_array($array)) {
        if (
next($array) === false) {
            return
false;
        } else {
            return
true;
        }
    } else {
        return
false;
    }
}

$array = array('fruit', 'melon');
if (
has_next($array)) {
    echo
next($array);
}

// prints 'melon'
?>

Since you do not pass the array by reference, its pointer is only moved inside the function.
Hope that helps.
up
2
bm at ANTISPAM dot solidwave dot com
15 years ago
Take care when replacing code using reset()/next() with code using foreach as foreach does not update the array's internal pointer.  This means you cannot, say, use next() to skip an element in foreach loop, or use current() within a function to get a reference to the current element.  You probably have code depending on this internal pointer and replacing it will be more work than you anticipated.

See http://www.php.net/foreach
up
2
court shrock
15 years ago
This code returns neighbors of the specified key.  The result will be empty if it doesn't have any neighbors.  My approach was to use the order of keys to determine neighbors, which is differnet from just getting the next/previous element in an array.  Feel free to point out stupidities :)

<?php

function array_neighbor($arr, $key)
{
   
krsort($arr);
   
$keys = array_keys($arr);
   
$keyIndexes = array_flip($keys);
   
   
$return = array();
    if (isset(
$keys[$keyIndexes[$key]-1]))
       
$return[] = $keys[$keyIndexes[$key]-1];
    if (isset(
$keys[$keyIndexes[$key]+1]))
       
$return[] = $keys[$keyIndexes[$key]+1];

    return
$return;
}

?>
up
1
lukasz at karapuda dot com
15 years ago
This function will return the previous,next neighbors of an array entry within an associative array. If the specified $key points to the last or first element of the array, the first or last keys of the array will be returned consecutively. This is an improved version of the same function posted earlier.

<?php
function array_neighbor($arr, $key)
{
  
$keys = array_keys($arr);
  
$keyIndexes = array_flip($keys);
 
  
$return = array();
   if (isset(
$keys[$keyIndexes[$key]-1])) {
      
$return[] = $keys[$keyIndexes[$key]-1];
   }
   else {
      
$return[] = $keys[sizeof($keys)-1];
   }
  
   if (isset(
$keys[$keyIndexes[$key]+1])) {
      
$return[] = $keys[$keyIndexes[$key]+1];
   }
   else {
      
$return[] = $keys[0];
   }
  
   return
$return;
}
?>
up
1
ThinkMedical at Gmail dot com
11 years ago
regarding references with foreach, you can use them directly. Obviating various posts which provide many lines of 'work arounds'.

$array = array(1,2,3,4,5);

foreach($array as &$value)

or use $key

foreach($array as $key => $value)
{
    $array[$key] = '...';
}
up
0
andy at andysdrawings dot co dot uk
11 months ago
brentimus' array_set_pointer function will only work if the array value is unique in the array, and none of the array values are FALSE. It would be more reliable to use key() instead of current(). For similar reasons it's better to check key() after calling next() to determine whether the next() element "exists". Simply checking the value returned by next() will produce a false negative when looking at, for example, the first element of the array: ['one', 0, 'three']

However, it also turns out that the copied array retains the original array's pointer, so array_set_pointer is not actually required here. The following should work:

<?php
function has_next(array &$array) {
   
$A_work = $array// $A_work is a copy of $array including its internal pointer.
   
next($A_work);
    if (
key($A_work) === NULL)
        return
false;
    else
        return
true;
}
?>
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0
notImportant
1 year ago
a more readable version of papipo's has_next function:

<?php
function has_next($array) {
   
$has_next = is_array($array) && next($array) !== false;

    return
$has_next;
}
?>

OR

<?php
function has_next($array) {
   
$has_next = false;
    if(
is_array($array)) {
       
$has_next = next($array) !== false;
    }

    return
$has_next;
}
?>
up
0
nigra
1 year ago
This function will return the previous,next neighbors of an array entry within an associative array. If the specified $key points to the last or first element of the array, the first or last keys of the array will be returned consecutively. This is an improved version of the same function posted earlier.

<?php
function array_neighbor($count, $key = null, $arRelated = array(), $cntRelated = 2)
{   
    if(
$count > 0 && isset($key))
    {       
       
$keyL = $count - 1;
       
$keyR = 1;
       
$arResult = array();
        for(
$i = 1; $i <= $cntRelated; $i++)
        {
            if(
$key == 0)
            {
                if((
$i % 2) == 0)
                {
                   
$curKey = $count - $keyL;
                   
$keyL--;
                }
                else
                {
                   
$curKey = $count - $keyR;
                   
$keyR++;
                }
            }
            else
            {
                if(
$arRelated[$i] >= $count - 1)
                {
                   
$curKey = 0;
                }
                else
                {
                   
$curKey = $arRelated[$i] + 1;
                }
            }
           
$arResult[$i] = $curKey;   
        }
        return
$arResult;
    }
}

$arr = range(0, 4);
$count = count($arr);

foreach(
$arr as $key => $v)
{
    if(
$arRelated = array_neighbor($count, $key, $arRelated))
    {
       
$arHeighbor[$key]['RELATED'] = $arRelated;
    }
}

echo
'<pre>';print_r($arHeighbor); echo '</pre>';
?>
Array
(
    [0] => Array
        (
            [RELATED] => Array
                (
                    [1] => 4
                    [2] => 1
                )

        )

    [1] => Array
        (
            [RELATED] => Array
                (
                    [1] => 0
                    [2] => 2
                )

        )

    [2] => Array
        (
            [RELATED] => Array
                (
                    [1] => 1
                    [2] => 3
                )

        )

    [3] => Array
        (
            [RELATED] => Array
                (
                    [1] => 2
                    [2] => 4
                )

        )

    [4] => Array
        (
            [RELATED] => Array
                (
                    [1] => 3
                    [2] => 0
                )

        )

)
up
0
double at dumpit dot de
9 years ago
PHP: 5.2.10-2ubuntu6.3 (default apt-get installation on actual, see Date, jaunty 9.10 Ubuntu Distro - G33kWoRDs)

Have a look at your array pointer if you copy an array - the pointer will be copied, too.

For example if you got this construct:
<?php
    $array
= array('zero','one','two','three','four','five','six','seven');
   
$array2 = $array;
   
next($array);
    echo
key($array);
    echo
key($array2);

   
// will output:
    // 1
    // 0
?>

But if you copy the array after you've setted the pointer, the pointer will be copied, too:
<?php
    $array
= array('zero','one','two','three','four','five','six','seven');
   
next($array);
   
$array2 = $array;
    echo
key($array);
    echo
key($array2);
  
   
// will output:
    // 1
    // 1
?>

What's more is, that foreach not resetting the pointer after walk through:
<?php

    $array
= array('zero','one','two','three','four','five','six','seven');
   
next($array);
   
$array2 = array();
    foreach(
$array AS $key => $value){
        echo
$key;
       
$array2[$key] = $value;
    }
    echo
var_dump(key($array));
    echo
key($array2);

   
// will output for foreach:
    // 0 1 2 3 4 5 6 7
    // and for the keys
    // NULL
    // 0
?>

The php-functions seems to reset the pointer on the given position after walk through (i don't know the internal handling - there could be used a copy of the array, too):
<?php

    $array
= array('zero','one','two','three','four','five','six','seven');
   
next($array);
   
$array2 = array_values($array);
    echo
key($array);
    echo
key($array2);

   
// will output:
    // 1
    // 0
?>

There are a lot Methods like array_merge($array) that will neither reset the pointer of $array nor copy the pointer to $array2. Have a look on this.
I Hope this was a little helpfull.
up
0
darkside at i dot ua
11 years ago
This class implements simple operations with array

<?php
class Steps {
   
    private
$all;
    private
$count;
    private
$curr;
   
    public function
__construct () {
     
     
$this->count = 0;
     
    }
   
    public function
add ($step) {
     
     
$this->count++;
     
$this->all[$this->count] = $step;
     
    }
   
    public function
setCurrent ($step) {
     
     
reset($this->all);
      for (
$i=1; $i<=$this->count; $i++) {
        if (
$this->all[$i]==$step) break;
       
next($this->all);
      }
     
$this->curr = current($this->all);
     
    }
   
    public function
getCurrent () {
     
      return
$this->curr;
     
    }
   
    public function
getNext () {
     
     
self::setCurrent($this->curr);
      return
next($this->all);
     
    }
       
  }
?>

usage example:

<?php
   $steps
= new Steps();
  
$steps->add('one');
  
$steps->add('two');
  
$steps->add('three');
  
$steps->setCurrent('one');
   echo
$steps->getCurrent()."<br />";
   echo
$steps->getNext()."<br />";
  
$steps->setCurrent('two');
   echo
$steps->getCurrent()."<br />";
   echo
$steps->getNext()."<br />";
?>
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-2
JumpIfBelow
4 years ago
After dealing with the fact that next() will either returns FALSE when there is no further element in the array or if the element itself is FALSE, I finally find a way to do a has_next() method, which will never fails. You can ignore and/or downvote my last comment, this it will be deleted.
Here is the code that work :
<?php
   
function has_next(array $a){
        return
next($a) !== false ?: each($a) !== false;
    }
?>
up
-4
tino at infeon dot com
13 years ago
this may be handy and i didnt know where else to post it.. i need a simple function to cycle through an array i eventually made it into a class so i could have multiple cycles.. if you like it or find it usefull please email me and let me know

class Cycle
{
    var $position;
    var $dataArray;
    var $dataArrayCount;
   
    function Cycle()
    {
        $this->dataArray = func_get_args();
        $this->dataArrayCount = count($this->dataArray);
    }
   
    function Display()
    {
        $this->position = (!isset($this->position) || $this->position >= ($this->dataArrayCount - 1)) ? 0 : $this->position += 1;
        return $this->dataArray[$this->position];
    }
   
}

$bgColor = new Cycle('#000000', '#FFFFFF', '#FF0000');

echo $bgcolor->Display();
//returns #000000
echo $bgcolor->Display();
//returns #FFFFFF
echo $bgcolor->Display();
//returns #FF0000
echo $bgcolor->Display();
//returns #000000
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