Php unset last element in array

array_pop

array_pop() извлекает и возвращает значение последнего элемента массива array , уменьшая размер array на один элемент.

Замечание: Эта функция при вызове сбрасывает указатель массива, переданного параметром.

Список параметров

Массив, из которого берётся значение.

Возвращаемые значения

Возвращает значение последнего элемента массива array . Если array пуст, будет возвращён null .

Примеры

Пример #1 Пример использования array_pop()

$stack = array( «orange» , «banana» , «apple» , «raspberry» );
$fruit = array_pop ( $stack );
print_r ( $stack );
?>

После этого в $stack будет только 3 элемента:

Array ( [0] => orange [1] => banana [2] => apple )

и raspberry будет присвоено переменной $fruit .

Смотрите также

• array_push() — Добавляет один или несколько элементов в конец массива
• array_shift() — Извлекает первый элемент массива
• array_unshift() — Добавляет один или несколько элементов в начало массива

User Contributed Notes 11 notes

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.

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.

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.

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 ]);
>
>
>

In a previous example .
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.

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

good luck 😉

alex.chacon@terra.com
Hi
Here there is a function that delete a elemente from a array and re calculate indexes

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 ;
>
?>

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.

Источник

array_pop

array_pop() pops and returns the value of the last element of array , shortening the array by one element.

Note: This function will reset() the array pointer of the input array after use.

Parameters

The array to get the value from.

Return Values

Returns the value of the last element of array . If array is empty, null will be returned.

Examples

Example #1 array_pop() example

$stack = array( «orange» , «banana» , «apple» , «raspberry» );
$fruit = array_pop ( $stack );
print_r ( $stack );
?>

After this, $stack will have only 3 elements:

Array ( [0] => orange [1] => banana [2] => apple )

and raspberry will be assigned to $fruit .

See Also

• array_push() — Push one or more elements onto the end of array
• array_shift() — Shift an element off the beginning of array
• array_unshift() — Prepend one or more elements to the beginning of an array

User Contributed Notes 11 notes

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.

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.

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.

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 ]);
>
>
>

In a previous example .
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.

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

good luck 😉

alex.chacon@terra.com
Hi
Here there is a function that delete a elemente from a array and re calculate indexes

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 ;
>
?>

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.

Источник

Php unset last element in array

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