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array_push

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

array_push — 一つ以上の要素を配列の最後に追加する

説明

array_push(array &$array, mixed ...$values): int

array_push()は、array をスタックとして処理し、渡された変数を array の最後に加えます。配列 array の長さは渡された変数の数だけ増加します。各 value1 毎に以下を繰り返すことと同じ効果があります。

<?php
$array[] = $var;
?>

各 value1 で繰り返されます。

注意: もし配列にひとつの要素を加えるために array_push() を使用するなら、関数を呼ぶオーバーヘッドがないので、$array[] = を使用するほうがいいです。

注意: 最初の引数が配列でない場合、array_push() は警告を発生させます。これは、PHP 7.1.0 より前のバージョンの、新規配列を生成する場合における $var[] の動作と異なっていました。

パラメータ

array: 入力の配列。
values: array の最後に追加する値。

戻り値

処理後の配列の中の要素の数を返します。

変更履歴

バージョン	説明
7.3.0	この関数は、1 つのパラメータでのみ呼び出すことができるようになりました。前は、少なくとも 2 つのパラメータが必要でした。

例

例1 array_push() の例

<?php
$stack = array("orange", "banana");
array_push($stack, "apple", "raspberry");
print_r($stack);
?>

上の例の出力は以下となります。

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

参考

array_pop() - 配列の末尾から要素を取り除く
array_shift() - 配列の先頭から要素を一つ取り出す
array_unshift() - 一つ以上の要素を配列の最初に加える

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User Contributed Notes 11 notes

down

1243

Rodrigo de Aquino ¶

12 years ago

If you're going to use array_push() to insert a "$key" => "$value" pair into an array, it can be done using the following:

    $data[$key] = $value;

It is not necessary to use array_push.

down

710

bxi at apparoat dot nl ¶

16 years ago

I've done a small comparison between array_push() and the $array[] method and the $array[] seems to be a lot faster.

<?php
$array = array();
for ($x = 1; $x <= 100000; $x++)
{
    $array[] = $x;
}
?>
takes 0.0622200965881 seconds

and

<?php
$array = array();
for ($x = 1; $x <= 100000; $x++)
{
    array_push($array, $x);
}
?>
takes 1.63195490837 seconds

so if your not making use of the return value of array_push() its better to use the $array[] way.

Hope this helps someone.

down

135

mrgreen dot webpost at gmail dot com ¶

8 years ago

Rodrigo de Aquino asserted that instead of using array_push to append to an associative array you can instead just do...

        $data[$key] = $value;

...but this is actually not true. Unlike array_push and even...

        $data[] = $value;

...Rodrigo's suggestion is NOT guaranteed to append the new element to the END of the array. For instance...

        $data['one'] = 1;
        $data['two'] = 2;
        $data['three'] = 3;
        $data['four'] = 4;
 
...might very well result in an array that looks like this...

       [ "four" => 4, "one" => 1, "three" => 3, "two" => 2 ]

I can only assume that PHP sorts the array as elements are added to make it easier for it to find a specified element by its key later. In many cases it won't matter if the array is not stored internally in the same order you added the elements, but if, for instance, you execute a foreach on the array later, the elements may not be processed in the order you need them to be.

If you want to add elements to the END of an associative array you should use the unary array union operator (+=) instead...

       $data['one'] = 1;
       $data += [ "two" => 2 ];
       $data += [ "three" => 3 ];
       $data += [ "four" => 4 ];

You can also, of course, append more than one element at once...

       $data['one'] = 1;
       $data += [ "two" => 2, "three" => 3 ];
       $data += [ "four" => 4 ];

Note that like array_push (but unlike $array[] =) the array must exist before the unary union, which means that if you are building an array in a loop you need to declare an empty array first...

       $data = [];
       for ( $i = 1; $i < 5; $i++ ) {
              $data += [ "element$i" => $i ];
       }

...which will result in an array that looks like this...

      [ "element1" => 1, "element2" => 2, "element3" => 3, "element4" => 4 ]

down

yhusky at qq dot com ¶

6 years ago

There is a mistake in the note by egingell at sisna dot com 12 years ago. The tow dimensional array will output "d,e,f", not "a,b,c".

<?php
$stack = array('a', 'b', 'c');
array_push($stack, array('d', 'e', 'f'));
print_r($stack);
?>

The above will output this:
Array (
  [0] => a
  [1] => b
  [2] => c
  [3] => Array (
     [0] => d
     [1] => e
     [2] => f
  )
)

down

willdemaine at gmail dot com ¶

16 years ago

If you're adding multiple values to an array in a loop, it's faster to use array_push than repeated [] = statements that I see all the time:

<?php
class timer
{
        private $start;
        private $end;

        public function timer()
        {
                $this->start = microtime(true);
        }

        public function Finish()
        {
                $this->end = microtime(true);
        }

        private function GetStart()
        {
                if (isset($this->start))
                        return $this->start;
                else
                        return false;
        }

        private function GetEnd()
        {
                if (isset($this->end))
                        return $this->end;
                else
                        return false;
        }

        public function GetDiff()
        {
                return $this->GetEnd() - $this->GetStart();
        }

        public function Reset()
        {
                $this->start = microtime(true);
        }

}

echo "Adding 100k elements to array with []\n\n";
$ta = array();
$test = new Timer();
for ($i = 0; $i < 100000; $i++)
{
        $ta[] = $i;
}
$test->Finish();
echo $test->GetDiff();

echo "\n\nAdding 100k elements to array with array_push\n\n";
$test->Reset();
for ($i = 0; $i < 100000; $i++)
{
        array_push($ta,$i);
}
$test->Finish();
echo $test->GetDiff();

echo "\n\nAdding 100k elements to array with [] 10 per iteration\n\n";
$test->Reset();
for ($i = 0; $i < 10000; $i++)
{
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
        $ta[] = $i;
}
$test->Finish();
echo $test->GetDiff();

echo "\n\nAdding 100k elements to array with array_push 10 per iteration\n\n";
$test->Reset();
for ($i = 0; $i < 10000; $i++)
{
        array_push($ta,$i,$i,$i,$i,$i,$i,$i,$i,$i,$i);
}
$test->Finish();
echo $test->GetDiff();
?>

Output

$ php5 arraypush.php
X-Powered-By: PHP/5.2.5
Content-type: text/html

Adding 100k elements to array with []

0.044686794281006

Adding 100k elements to array with array_push

0.072616100311279

Adding 100k elements to array with [] 10 per iteration

0.034690141677856

Adding 100k elements to array with array_push 10 per iteration

0.023932933807373

down

raat1979 at gmail dot com ¶

8 years ago

Unfortunately array_push returns the new number of items in the array
It does not give you the key of the item you just added, in numeric arrays you could do -1, you do however need to be sure that no associative key exists as that would break the assumption

It would have been better if array_push would have returned the key of the item just added like the below function
(perhaps a native variant would be a good idea...)

<?php

if(!function_exists('array_add')){
    function array_add(array &$array,$value /*[, $...]*/){
        $values = func_get_args();     //get all values
        $values[0]= &$array;        //REFERENCE!
        $org=key($array);              //where are we?
        call_user_func_array('array_push',$values);
        end($array);                 // move to the last item
        $key = key($array);         //get the key of the last item
        if($org===null){
            //was at eof, added something, move to it
            return $key;
        }elseif($org<(count($array)/2)){ //somewhere in the middle +/- is fine
            reset($array);
            while (key($array) !== $org) next($List);
        }else{
            while (key($array) !== $org) prev($List);
        }
        return $key;
    }
}
echo "<pre>\n";
$pr = array('foo'=>'bar','bar'=>'foo');
echo "Taken array;"; 
print_r($pr);

echo "\npush 1 returns ".array_push($pr,1)."\n";
echo "------------------------------------\n";
$pr = array('foo'=>'bar','bar'=>'foo');
echo "\npush 2 returns ".array_push($pr,1,2)."\n";
echo "------------------------------------\n";
$pr = array('foo'=>'bar','bar'=>'foo');
echo "\n add 1 returns ".array_add($pr,2)."\n\n";
echo "------------------------------------\n";
$pr = array('foo'=>'bar','bar'=>'foo');
echo "\n add 2 returns ".array_add($pr,1,2)."\n\n";
echo "<pre/>\n\n";
?>
Outputs:
Taken array;Array
(
    [foo] => bar
    [bar] => foo
)

push 1 returns 3
------------------------------------

push 2 returns 4
------------------------------------

 add 1 returns 0

------------------------------------

 add 2 returns 1

down

egingell at sisna dot com ¶

18 years ago

If you push an array onto the stack, PHP will add the whole array to the next element instead of adding the keys and values to the array. If this is not what you want, you're better off using array_merge() or traverse the array you're pushing on and add each element with $stack[$key] = $value.

<?php

$stack = array('a', 'b', 'c');
array_push($stack, array('d', 'e', 'f'));
print_r($stack);

?>
The above will output this:
Array (
  [0] => a
  [1] => b
  [2] => c
  [3] => Array (
     [0] => a
     [1] => b
     [2] => c
  )
)

down

helpmepro1 at gmail dot com ¶

15 years ago

elegant php array combinations algorithm

<?

//by Shimon Dookin

function get_combinations(&$lists,&$result,$stack=array(),$pos=0)
{
 $list=$lists[$pos];
 if(is_array($list))
  foreach($list as $word)
  {
   array_push($stack,$word);
   if(count($lists)==count($stack))
    $result[]=$stack;
   else
    get_combinations($lists,$result,$stack,$pos+1);
   array_pop($stack);
  }
}

$wordlists= array( array("shimon","doodkin") , array("php programmer","sql programmer","mql metatrader programmer") );

get_combinations($wordlists,$combinations);

echo '<xmp>';
print_r($combinations);

?>

down

gfuente at garrahan dot gov dot ar ¶

7 years ago

If the element to be pushed onto the end of array is an array you will receive the following error message: 

Unknown Error, value: [8] Array to string conversion

I tried both: (and works, but with the warning message)

            $aRol = array( $row[0], $row[1], $row[2] );
            $aRoles[] = $aRol;

and 
            array_push( $aRoles, $aRol);

The correct way:

            $cUnRol = implode("(",array( $row[0], $row[1], $row[2] ) ); 
            array_push( $aRoles, $cUnRol ); 

thanks.

down

andrew at cgipro dot com ¶

19 years ago

Need a real one-liner for adding an element onto a new array name?

$emp_list_bic = $emp_list + array(c=>"ANY CLIENT");

CONTEXT...
drewdeal: this turns out to be better and easier than array_push()
patelbhadresh: great!... so u discover new idea...
drewdeal: because you can't do:   $emp_list_bic = array_push($emp_list, c=>"ANY CLIENT");
drewdeal: array_push returns a count and affects current array.. and does not support set keys!
drewdeal: yeah. My one-liner makes a new array as a derivative of the prior array

down

steve at webthoughts d\ot ca ¶

19 years ago

Further Modification on the array_push_associative function
1.  removes seemingly useless array_unshift function that generates php warning
2.  adds support for non-array arguments

<?
// Append associative array elements
function array_push_associative(&$arr) {
   $args = func_get_args();
   foreach ($args as $arg) {
       if (is_array($arg)) {
           foreach ($arg as $key => $value) {
               $arr[$key] = $value;
               $ret++;
           }
       }else{
           $arr[$arg] = "";
       }
   }
   return $ret;
}

$items = array("here" => "now");
$moreitems = array("this" => "that");

$theArray = array("where" => "do we go", "here" => "we are today");
echo array_push_associative($theArray, $items, $moreitems, "five") . ' is the size of $theArray.<br />';
    
echo "<pre>";
print_r($theArray);
echo "</pre>";

?>

Yields: 

4 is the size of $theArray.
Array
(
    [where] => do we go
    [here] => now
    [this] => that
    [five] => 
)

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array_push

説明

パラメータ

戻り値

変更履歴

例

参考

Found A Problem?

User Contributed Notes 11 notes