array_push
array_push() treats array as a stack, and pushes the passed variables onto the end of array . The length of array increases by the number of variables pushed. Has the same effect as:
Note: If you use array_push() to add one element to the array, it’s better to use $array[] = because in that way there is no overhead of calling a function.
Note: array_push() will raise a warning if the first argument is not an array. This differed from the $var[] behaviour where a new array was created, prior to PHP 7.1.0.
Parameters
The values to push onto the end of the array .
Return Values
Returns the new number of elements in the array.
Changelog
| Version | Description |
|---|---|
| 7.3.0 | This function can now be called with only one parameter. Formerly, at least two parameters have been required. |
Examples
Example #1 array_push() example
$stack = array( «orange» , «banana» );
array_push ( $stack , «apple» , «raspberry» );
print_r ( $stack );
?>
The above example will output:
Array ( [0] => orange [1] => banana [2] => apple [3] => raspberry )
See Also
- array_pop() — Pop the element off the end of array
- array_shift() — Shift an element off the beginning of array
- array_unshift() — Prepend one or more elements to the beginning of an array
User Contributed Notes 36 notes
If you’re going to use array_push() to insert a «$key» => «$value» pair into an array, it can be done using the following:
It is not necessary to use array_push.
I’ve done a small comparison between array_push() and the $array[] method and the $array[] seems to be a lot faster.
$array = array();
for ( $x = 1 ; $x $array [] = $x ;
>
?>
takes 0.0622200965881 seconds
$array = array();
for ( $x = 1 ; $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.
Rodrigo de Aquino asserted that instead of using array_push to append to an associative array you can instead just do.
. but this is actually not true. Unlike array_push and even.
. 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.
. which will result in an array that looks like this.
[ «element1» => 1, «element2» => 2, «element3» => 3, «element4» => 4 ]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. )
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 «\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 «\n\n» ;
?>
Outputs:
Taken array;Array
(
[foo] => bar
[bar] => foo
)
There is problem with pushing references to array, introduced in PHP 5.4 — did someone decide it is not needed?
In PHP 5.3 this could be used:
$A=array(); array_push($A,1); $c=2; array_push($A,&$c); print_r($A); $c=3; print_r($A);
Array ( [0] => 1 [1] => 2 )
Array ( [0] => 1 [1] => 3 )
Think of Reference as a pointer in other languages.
This function is needed for example to push parameters for MySql query:
$params=array(); array_push($params,&$field1); array_push($params,&$field2); array_unshift($params,’ss’);
call_user_func_array(array($Query,’bind_param’),$params);
This code causes fatal error in PHP 5.4 and depending on server configuration it may not even be reported why.
A workarround to allow pushing references to array is this:
$A=array(); $A[]=1; $c=2; $A[]=&$c; print_r($A); $c=3; print_r($A);
$params=array(); $params[]=&$field1; $params[]=&$field2; array_unshift($params,’ss’);
call_user_func_array(array($Query,’bind_param’),$params);
(in actual code, the fields are specified dynamically and iterated in for-loop. )
This seems working both on PHP 5.3 and PHP 5.6 .
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:
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 []
Adding 100k elements to array with array_push
Adding 100k elements to array with [] 10 per iteration
Adding 100k elements to array with array_push 10 per iteration
After using array_push you may wish to read the top (last) array element one or more times before using array_pop. To read the top array element efficiently, use the ‘current’ function.
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».
$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
)
)
A common operation when pushing a value onto a stack is to address the value at the top of the stack.
This can be done easily using the ‘end’ function:
$top = end ( $stack );
?>
Note: See the ‘end’ function for details about its side effect on the seldom used internal array pointer.
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.
$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
)
)
If you want to preserve the keys in the array, use the following:
function array_pshift (& $array ) <
$keys = array_keys ( $array );
$key = array_shift ( $keys );
$element = $array [ $key ];
unset( $array [ $key ]);
return $element ;
>
?>
This is how I add all the elements from one array to another:
$oneArray = [ ‘d’ , ‘e’ , ‘f’ ];
$anotherArray = [ ‘a’ , ‘b’ , ‘c’ ];
array_push ( $anotherArray , . $oneArray );
//[‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’];
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);
$cUnRol = implode(«(«,array( $row[0], $row[1], $row[2] ) );
array_push( $aRoles, $cUnRol );
When developing a pocketmine plugin, a good way to add stuff to a YAML table is
$table=$this->config->get(«Table»);
array_push($table, «New Value for table»);
$this->config->set(«Table», $table);
Skylifter notes on 20-Jan-2004 that the [] empty bracket notation does not return the array count as array_push does. There’s another difference between array_push and the recommended empty bracket notation.
Empy bracket doesn’t check if a variable is an array first as array_push does. If array_push finds that a variable isn’t an array it prints a Warning message if E_ALL error reporting is on.
So array_push is safer than [], until further this is changed by the PHP developers.
elegant php array combinations algorithm
function get_combinations(&$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);
>
>
$wordlists= array( array(«shimon»,»doodkin») , array(«php programmer»,»sql programmer»,»mql metatrader programmer») );
I think it worked in the past or i havent test it good enough. :-/
(once it worked, once [] was faster than array_push, the past 😀 ):
php -r ‘$a = array(1,2); $a += array(3,4); print_r($a);’
Array (
[0] => 1
[1] => 2
)
php -r ‘$a = array(1,2); $b = array(3,4);$c = $a + $b; print_r($c);’
Array (
[0] => 1
[1] => 2
)
php -r ‘$a = array(1,2); $b = array(2=>3,3=>4);$c = $a + $b; print_r($c);’
Array (
[0] => 1
[1] => 2
[2] => 3
[3] => 4
)
I did a performance check, and I saw, if you push more than one value it can be faster the array push, that the normal $array[] version.
Case 1: $array[] = something;
Case 2: array_push($array, $value);
Case 3: array_push($array, $value1, $value2, $value3 [. ]); $values are definied
Case 4: array_push($array, $value1, $value2, $value3 [. ]); $values are definied, when $array is not empty
Case 5: Case1 + Case 3
Case 6: Result array contains some value (Case 4)
Case 7: Result array contains same value as the push array (Case 4)
————————————————————————————————————
~~~~~~~~~~~~ Case 1 ~~~~~~~~~~~~
Times: 0.0310 0.0300 0.0290 0.0340 0.0400 0.0440 0.0480 0.0550 0.0570 0.0570
Min: 0.0290
Max: 0.0570
Avg: 0.0425
~~~~~~~~~~~~ Case 2 ~~~~~~~~~~~~
Times: 0.3890 0.3850 0.3770 0.4110 0.4020 0.3980 0.4020 0.4060 0.4130 0.4200
Min: 0.3770
Max: 0.4200
Avg: 0.4003
~~~~~~~~~~~~ Case 3 ~~~~~~~~~~~~
Times: 0.0200 0.0220 0.0240 0.0340 0.0360 0.0410 0.0460 0.0500 0.0520 0.0520
Min: 0.0200
Max: 0.0520
Avg: 0.0377
~~~~~~~~~~~~ Case 4 ~~~~~~~~~~~~
Times: 0.0200 0.0250 0.0230 0.0260 0.0330 0.0390 0.0460 0.0510 0.0520 0.0520
Min: 0.0200
Max: 0.0520
Avg: 0.0367
~~~~~~~~~~~~ Case 5 ~~~~~~~~~~~~
Times: 0.0260 0.0250 0.0370 0.0360 0.0390 0.0440 0.0510 0.0520 0.0530 0.0560
Min: 0.0250
Max: 0.0560
Avg: 0.0419
~~~~~~~~~~~~ Case 6 ~~~~~~~~~~~~
Times: 0.0340 0.0280 0.0370 0.0410 0.0450 0.0480 0.0560 0.0580 0.0580 0.0570
Min: 0.0280
Max: 0.0580
Avg: 0.0462
~~~~~~~~~~~~ Case 7 ~~~~~~~~~~~~
Times: 0.0290 0.0270 0.0350 0.0410 0.0430 0.0470 0.0540 0.0540 0.0550 0.0550
Min: 0.0270
Max: 0.0550
Avg: 0.044
Tester code:
// Case 1
$startTime = microtime(true);
$array = array();
for ($x = 1; $x $array[] = $x;
>
$endTime = microtime(true);
// Case 2
$startTime = microtime(true);
$array = array();
for ($x = 1; $x array_push($array, $x);
>
$endTime = microtime(true);
// Case 3
$result = array();
$array2 = array(&$result)+$array;
$startTime = microtime(true);
call_user_func_array(«array_push», $array2);
$endTime = microtime(true);
// Case 4
$result = array();
for ($x = 1; $x $result[] = $x;
>
$array2 = array(&$result)+$array;
$startTime = microtime(true);
call_user_func_array(«array_push», $array2);
$endTime = microtime(true);
// Case 5
$result = array();
$startTime = microtime(true);
$array = array(&$result);
for ($x = 1; $x $array[] = $x;
>
$endTime = microtime(true);
// Case 6
$result = array(1,2,3,4,5,6);
$startTime = microtime(true);
$array = array(&$result);
for ($x = 1; $x $array[] = $x;
>
$endTime = microtime(true);
// Case 7
$result = array();
for ($x = 1; $x $result[] = $x;
>
$startTime = microtime(true);
$array = array(&$result);
for ($x = 1; $x $array[] = $x;
>
$endTime = microtime(true);