array_pop

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

array_popEstrae l'elemento alla fine dell'array

Descrizione

array_pop(array $array): mixed

array_pop() estrae e restituisce l'ultimo valore di array, accorciando array di un elemento. Se array è vuoto (o non è un array), viene restituito null.

Nota: Questa funzione farà il reset() del puntatore dell'array dopo l'uso.

Example #1 esempio di array_pop()

<?php
$pila
= array("arancia", "banana", "mela", "lampone");
$frutto = array_pop($pila);
print_r($pila);
?>

Dopo questa istruzione, $pila avrà solo 3 elementi:

Array
(
    [0] => arancia
    [1] => banana
    [2] => mela
)

e lampone verrà assegnato alla variabile $frutto.

Avviso

Questa funzione può restituire il Booleano false, ma può anche restituire un valore non-Booleano valutato come false. Fare riferimento alla sezione Booleans per maggiori informazioni. Usare l'operatore === per controllare il valore restituito da questa funzione.

Vedere anche array_push(), array_shift() e array_unshift().

add a note add a note

User Contributed Notes 16 notes

up
57
elad dot yosifon at gmail dot com
10 years ago
Notice:
the complexity of array_pop() is O(1).
the complexity of array_shift() is O(n).
array_shift() requires a re-index process on the array, so it has to run over all the elements and index them.
up
7
mcgroovin at gmail dot com
15 years ago
I wrote a simple function to perform an intersect on multiple (unlimited) arrays.

Pass an array containing all the arrays you want to compare, along with what key to match by.

<?php
function multipleArrayIntersect($arrayOfArrays, $matchKey)
{
   
$compareArray = array_pop($arrayOfArrays);
   
    foreach(
$compareArray AS $key => $valueArray){
        foreach(
$arrayOfArrays AS $subArray => $contents){
            if (!
in_array($compareArray[$key][$matchKey], $contents)){
                unset(
$compareArray[$key]);
            }
        }
    }

    return
$compareArray;
}
?>
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3
rmondragon at gmail dot com
18 years ago
In a previous example ...
<?php
function array_trim ( $array, $index ) {
   if (
is_array ( $array ) ) {
     unset (
$array[$index] );
    
array_unshift ( $array, array_shift ( $array ) );
     return
$array;
     }
   else {
     return
false;
     }
   }
?>

This have a problem. if u unset the last value and then use
<?
array_unshift ( $array, array_shift ( $array ) );
?>

will return a :  Array ( [0] => )
so u can fix it using...

<?php
if (count($array) > 0) array_unshift ( $values, array_shift ( $values ) );           
?>

good luck ;)
up
2
qeremy
12 years ago
For the sake of array_unshift()
:)

<?php
function array_unpop(&$arr) {
   
$args = func_get_args(); unset($args[0]);
   
$tarr = array();
    foreach (
$args as $arg) {
       
$tarr[] = $arg;
    }
   
$arr = array_merge($arr, $tarr);
}

$queue = array("orange", "banana");
array_unpop($queue, "apple", "raspberry");
print_r($queue);
?>

Array
(
    [0] => orange
    [1] => banana
    [2] => apple
    [3] => raspberry
)
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2
doyley3731 at gmail dot com
16 years ago
I had a problem when using this function because my array was made up entirley of numbers, so I have made my own function.  Hopefully it will be useful to somebody.

function array_trim_end($array){

$num=count($array);
$num=$num-1;
unset($array[$num]);

return $array;
}
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0
noreply at i-asm dot com
2 years ago
Note that array_pop doesn't issue ANY warning or error if the array is already empty when you try to pop something from it. This is bizarre! And it will cause cascades of errors that are hard to resolve without knowing the real cause.

Rather than an error, it silently returns a NULL object, it appears, so in my case I ended up with warnings elsewhere about accessing elements of arrays with invalid indexes, as I was expecting to have popped an array. This behaviour (and the lack of any warning, when many trivial things are complained about verbosely) is NOT noted in the manual above. Popping an already empty stack should definitely trigger some sort of notice, to help debugging.

Sure, it's probably good practice to wrap the pop in an if (count($array)) but that should be suggested in the manual, if there's no error returned for trying something that should fail and obviously isn't expected to return a meaningful result.
up
1
Alex Chac?n
21 years ago
alex.chacon@terra.com
Hi
Here there is a function that delete a elemente from a array and re calculate indexes

<?php
function eliminarElementoArreglo ($array, $indice)
{
    if (
array_key_exists($indice, $array))
    {
       
$temp = $array[0];
       
$array[0] = $array[$indice];
       
$array[$indice] = $temp;
       
array_shift($array);

       
//reacomodamos ?ndices
       
for ($i = 0 ; $i < $indice ; $i++)
        {
           
$dummy = $array[$i];
           
$array[$i] = $temp;
           
$temp = $dummy;
        }
    }
    return
$array;
}
?>
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0
Orsi
16 years ago
Hi,

Here is a simple function which delete one element from the array (with value):
<?php
/*
* This function deletes the given element from a one-dimension array
* Parameters: $array:    the array (in/out)
*             $deleteIt: the value which we would like to delete
*             $useOldKeys: if it is false then the function will re-index the array (from 0, 1, ...)
*                          if it is true: the function will keep the old keys
* Returns true, if this value was in the array, otherwise false (in this case the array is same as before)
*/
function deleteFromArray(&$array, $deleteIt, $useOldKeys = FALSE)
{
   
$tmpArray = array();
   
$found = FALSE;
    foreach(
$array as $key => $value)
    {
        if(
$value !== $deleteIt)
        {
            if(
FALSE === $useOldKeys)
            {
               
$tmpArray[] = $value;
            }
            else
            {
               
$tmpArray[$key] = $value;
            }
        }
        else
        {
           
$found = TRUE;
        }
    }
  
   
$array = $tmpArray;
  
    return
$found;
}
?>

Maybe it will help somebody...
up
0
Anonymous
19 years ago
strrchr is a lot more useful than the other example using array_pop for finding the extension of a file. For example:

<?php
$ext
= strrchr($filename, ".");
?>

$ext will contain the extension of the file, including a ".", if the file has an extension, and FALSE if the file has no extension. If the file has multiple extensions, such as "filename.tar.gz", then this construction will just return the last extension.
up
-1
Anonymous
10 years ago
Strict Standards will be thrown out if you put exploded array in array_pop:
<?php
$a
= array_pop(explode(",", "a,b,c"));
echo
$a;
?>

You will see:
PHP Strict Standards:  Only variables should be passed by reference in - on line 2

Strict Standards: Only variables should be passed by reference in - on line 2
c

Notice that, you should assign a variable for function explode, then pass the variable reference into array_pop to avoid the Strict Standard warning.
up
-1
sonetti at hotmail dot com
16 years ago
@smp_info
I think you are still tired. What would be wrong with:

<?php
$array
= array('one', 'two', 'three', 'four');

//pop the last element off
array_pop($array);

//$array == array('one', 'two', 'three');
?>

As the documentation clearly notes, array_pop() not only returns the last element, but actually removes it from the array wich is passed by reference. Calling array_diff is a waste of resources.
up
-3
eddie at metafoundry dot com
19 years ago
Quick way to get the extension from a file name using array_pop:

$ext = array_pop(explode(".",$filename));
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-3
Igor Feghali
15 years ago
Beware that array_pop() returns a copy of the element (even if the array element is a reference). That means you will get different results on PHP 4 and 5 when dealing with objects.

<?php
$a
= new stdClass();
$a->foo = 'bar';

$arr = array(&$a);
$b = array_pop($arr);

$b->foo = 'baz';

var_dump($a);
?>

Output of PHP 5.2.8:
object(stdClass)#1 (1) {
  ["foo"]=>
  string(3) "baz"
}

Output of PHP 4.4.9:
object(stdClass)(1) {
  ["foo"]=>
  string(3) "bar"
}

For more information please refer to:
http://br2.php.net/manual/en/language.oop5.references.php
up
-3
ryan8613(at)hotmail(dot)com
20 years ago
A function that may help some out, considering it's pretty much the one mentioned previously...

<?php
function array_trim($arr, $indice) {
        if(!isset(
$indice)) {
               
$indice = count($arr)-1;
        }
        unset(
$arr[$indice]);
       
array_shift($arr);
        return
$arr;
}
?>

It cuts the given index value off of the array, but without the shift, if  the 'index' value isn't given, it cuts off the end value.
up
-3
Anonymous
19 years ago
A function to delete an array value that recalculates the index ( its very short and easy to understand ).
Hope this might help someone...

<?php
/* Usage:
    $array : Array
    $indey : Integer
   
    The value of $array at the index $index will be
    deleted by the function.
*/
function array_trim ( $array, $index ) {
   if (
is_array ( $array ) ) {
      unset (
$array[$index] );
     
array_unshift ( $array, array_shift ( $array ) );
      return
$array;
      }
   else {
      return
false;
      }
   }
?>
up
-10
Anonymous
8 years ago
Let's "do stuff" with array_pop()

<?php

$dependecyInjection
= ['globalState' => 'isHorrible'];

$workQueue = array_reverse($workQueue); // O(n)
// While we have stuff to do..... = [[ {function}, $params.... ], [], []...]
while (!empty($workQueue)) {

 
// O(1) : And resize array. (maybe also memory size ?)
 
$work = array_pop($workQueue);

 
// If not `muted`, invoke the worker function....
 
if (isset($work[0])) {
   
$processor = array_shift($work);
    if (
$moreWork = $processor->__invoke($work, $dependecyInjection)) { // <== Do stuff.
      // O(n) : add new stuff to the END of array ! (FIFO)
     
$outputCommands += array_reverse($moreWork);
    }
  }
}
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