array_push

(PHP 4, PHP 5)

array_push --  将一个或多个单元压入数组的末尾(入栈)

说明

int array_push ( array &array, mixed var [, mixed ...] )

array_push()array 当成一个栈,并将传入的变量压入 array 的末尾。array 的长度将根据入栈变量的数目增加。和如下效果相同:
<?php
$array
[] = $var;
?>
并对每个 var 重复以上动作。

返回数组新的单元总数。

例子 1. array_push() 例子

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

本例将使 $stack 具有如下单元:

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

注: 如果用 array_push() 来给数组增加一个单元,还不如用 $array[] = ,因为这样没有调用函数的额外负担。

注: 如果第一个参数不是数组,array_push() 将发出一条警告。这和 $var[] 的行为不同,后者会新建一个数组。

参见 array_pop()array_shift()array_unshift()


add a note add a note User Contributed Notes
antido at gmail dot com
03-Aug-2006 04:04
Simple data object implementation:

<?php

/**
 * Data object
 *
 * @version 0.6
 * @author Tom Reitsma <antido@gmail.com>
 */
Class DataObject
{
  
/**
     * @var int $ptr
     */
  
private $ptr = 0;
  
  
/**
     * @var array $data
     */
  
private $data = array();
  
  
/**
     * Class constructor
     */
  
public function __construct($anArray=false)
   {
       if(
$anArray != false)
       {
           if(
is_array($anArray))
           {
              
$this->data[] = $anArray;
           }
       }
   }
  
  
/**
     * Fetches the data under the pointer
     *
     * @return String if there is still data left under the pointer, false if the end has been reached
     */
  
public function fetch()
   {
       if(isset(
$this->data[$this->ptr]))
       {
           return
$this->data[$this->ptr++];
       }
      
       return
false;
   }
  
  
/**
     * Moves to the next row in the data object
     *
     * @return boolean
     */
  
public function moveNext()
   {
      
$newPtr = $this->ptr + 1;
      
       if(isset(
$this->data[$newPtr]))
       {
          
$this->ptr = $newPtr;
           return
true;
       }
      
       return
false;
   }
  
  
/**
     * Moves to the previous row in the data object
     *
     * @return boolean
     */
  
public function movePrevious()
   {
      
$newPtr = $this->ptr - 1;
      
       if(isset(
$this->data[$newPtr]))
       {
           return
$this->data[$newPtr];
       }
      
       return
false;
   }
  
  
/**
     * Pushes an element onto the array
     *
     * @param String or an array $input
     * @return number of elements
     */
  
public function push($input)
   {
       if(
$this->getNumRows() > 0)
       {
           return
array_push($this->data, $input);
       }
       else
       {
           return
$this->data[] = $input;
       }
   }
  
  
/**
     * Counts the number of rows
     */
  
public function getNumRows()
   {
       return
count($this->data);
   }
}

?>
Marc Bernet
16-May-2006 12:18
A small and basic implementation of a stack without using an array.

class node
{
       var $elem;
       var    $next;
}
class stack
{
   var $next;
   function pop()
   {
       $aux=$this->next->elem;
       $this->next=$this->next->next;
       return $aux;
   }
   function push($obj)
   {
       $nod=new node;
       $nod->elem=$obj;
       $nod->next=$this->next;
       $this->next=$nod;
   }
   function stack()
   {
       $this->next=NULL;
   }   
}
krristaps at inbox dot lv
16-Mar-2006 07:52
Here is the smallest chunk of php code describing data structure called stack:

<?php
class stack{
       var
$memory=array();
       function
push($value){
              
$this->memory[]=$value;
       }
       function
pop(){
              
$count=$this->count();
               if (
$count){
                      
$value=$this->memory[$count-1];
                       unset(
$this->memory[$count-1]);
                       return
$value;
               }
               else return
false;
       }
       function
count(){
               return
count($this->memory);
       }
};
?>
richard dot udo at gmail dot com
09-Feb-2006 07:05
Just a typo i think but the code below will actually produce

Array
(
   [0] => a
   [1] => b
   [2] => c
   [3] => Array
       (
           [0] => d
           [1] => e
           [2] => f
       )
)
egingell at sisna dot com
28-Jan-2006 10:06
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
  )
)
steve at webthoughts d\ot ca
13-Nov-2005 08:02
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] =>
)
ludvig dot ericson at gmail dot com
31-Oct-2005 09:32
Previous comment was not fully imitating the array_push behaviour,
1) does not return number of items pushed
2) can only handle one array to push

> Revised associative_push function with absolute reference of arg1 array; left unchanged if arg2 is empty.

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

$theArray = array();
echo
array_push_associative($theArray, $items, $moreitems) . ' items added to $theArray.';
?>
john
20-Oct-2005 04:33
A variation of kamprettos' associative array push:

// append associative array elements
function associative_push($arr, $tmp) {
  if (is_array($tmp)) {
   foreach ($tmp as $key => $value) {
     $arr[$key] = $value;
   }
   return $arr;
  }
  return false;
}

$theArray = array();
$theArray = associative_push($theArray, $items);
kamprettos at yahoo dot com Teguh Iskanto
19-Sep-2005 08:33
Looking for a way to push data into an associative array and frustrated to know that array_push() can't do the job ?

here's my Scenario :
-------------------
I need to relate system command output into an associative array like these :

[sge@digital_db work]$ /usr/local/apache/htdocs/work/qhost.sh -h t1 -F | awk '{if(NR>4) print $1}' | sed  's/hl://g'
arch=lx24-amd64
num_proc=2.000000
mem_total=3.808G
swap_total=3.907G
virtual_total=7.715G
load_avg=0.000000
load_short=0.000000
load_medium=0.000000
load_long=0.000000
mem_free=3.510G
swap_free=3.907G
virtual_free=7.417G
mem_used=305.242M
swap_used=0.000
virtual_used=305.242M
cpu=0.000000
np_load_avg=0.000000
np_load_short=0.000000
np_load_medium=0.000000
np_load_long=0.000000

how I did it :
<? php

# get into the system command output
$assoc_cmd =`$work_dir/qhost.sh -h $host_resource -F | awk '{if(NR>4) print $1}'| sed  's/hl://g' ` ;

# split the "\n" character
$assoc_row = explode("\n", chop($assoc_cmd));

# get the index row
$idx_row  = count($assoc_row) - 1 ;

# initialize the associative array
$host_res_array = array();

for (
$i = 0 ; $i<= $idx_row ; $i++)
       {     
              
# get params & values
              
list($host_param,$host_val) = explode("=",$assoc_row[$i]);

              
# populate / push data to assoc array
              
$host_res_array[$host_param]= $host_val ;
       }   

echo
"<pre> Architecture : </pre>\n" ;
echo
$host_res_array['arch'] ;
echo
"<pre> Mem Total    : </pre>\n" ;
echo
$host_res_array['mem_tot'];

?>

Hope this helps ! :)
bk at quicknet dot nl
04-Sep-2005 04:51
Add elements to an array before or after a specific index or key:

<?php

/**
 * @return array
 * @param array $src
 * @param array $in
 * @param int|string $pos
*/
function array_push_before($src,$in,$pos){
   if(
is_int($pos)) $R=array_merge(array_slice($src,0,$pos), $in, array_slice($src,$pos));
   else{
       foreach(
$src as $k=>$v){
           if(
$k==$pos)$R=array_merge($R,$in);
          
$R[$k]=$v;
       }
   }return
$R;
}

/**
 * @return array
 * @param array $src
 * @param array $in
 * @param int|string $pos
*/
function array_push_after($src,$in,$pos){
   if(
is_int($pos)) $R=array_merge(array_slice($src,0,$pos+1), $in, array_slice($src,$pos+1));
   else{
       foreach(
$src as $k=>$v){
          
$R[$k]=$v;
           if(
$k==$pos)$R=array_merge($R,$in);
       }
   }return
$R;
}

// Examples:

$src=array("A","B","C");
$in=array("X","Y");

var_dump(array_push_before($src,$in,1));
/* array_push_before, no-key array
array(5) {
  [0]=>
  string(1) "A"
  [1]=>
  string(1) "X"
  [2]=>
  string(1) "Y"
  [3]=>
  string(1) "B"
  [4]=>
  string(1) "C"
}*/

var_dump(array_push_after($src,$in,1));
/* array_push_after, no-key array
array(5) {
  [0]=>
  string(1) "A"
  [1]=>
  string(1) "B"
  [2]=>
  string(1) "X"
  [3]=>
  string(1) "Y"
  [4]=>
  string(1) "C"
}*/

$src=array('a'=>"A",'b'=>"B",'c'=>"C");
$in=array('x'=>"X",'y'=>"Y");

var_dump(array_push_before($src,$in,1));
/* array_push_before, key array, before index insert
array(5) {
  ["a"]=>
  string(1) "A"
  ["x"]=>
  string(1) "X"
  ["y"]=>
  string(1) "Y"
  ["b"]=>
  string(1) "B"
  ["c"]=>
  string(1) "C"
}*/

var_dump(array_push_before($src,$in,'b'));
/* array_push_before, key array, before key insert
array(5) {
  ["a"]=>
  string(1) "A"
  ["x"]=>
  string(1) "X"
  ["y"]=>
  string(1) "Y"
  ["b"]=>
  string(1) "B"
  ["c"]=>
  string(1) "C"
}*/

var_dump(array_push_after($src,$in,1));
/* array_push_after, key array, after index insert
array(5) {
  ["a"]=>
  string(1) "A"
  ["b"]=>
  string(1) "B"
  ["x"]=>
  string(1) "X"
  ["y"]=>
  string(1) "Y"
  ["c"]=>
  string(1) "C"
}*/

var_dump(array_push_after($src,$in,'b'));
/* array_push_after, key array, after key insert
array(5) {
  ["a"]=>
  string(1) "A"
  ["b"]=>
  string(1) "B"
  ["x"]=>
  string(1) "X"
  ["y"]=>
  string(1) "Y"
  ["c"]=>
  string(1) "C"
}*/

?>
ciprian dot amariei at gmail com
31-Aug-2005 05:47
regarding the speed of oneill's solution to insert a value into a non-associative array,  I've done some tests and I found that it behaves well if you have a small array and more insertions, but for a huge array and a little insersions I sugest  using this function:

function array_insert( &$array, $index, $value ) {
   $cnt = count($array);
 
   for( $i = $cnt-1; $i >= $index; --$i ) {
       $array[ $i + 1 ] = $array[ $i ];
   }
   $array[$index] = $value;
}

or if you are a speed adicted programmer (same situation: big array, few insertions) use this:

array_splice ( $array, $offset, 0, $item );

item may also be an array of values ;).
Phil Davies
18-Jul-2005 06:51
As someone pointed out the array_push() function returns the count of the array not the key of the new element. As it was the latter function i required i wrote this very simple replacement.

function array_push2(&$array,$object,$key=null){
   $keys = array_keys($array);
   rsort($keys);
   $newkey = ($key==null)?$keys[0]+1:$key;
   $array[$newkey] = $object;
   return $newkey;
}
oneill at c dot dk
04-Jun-2005 04:50
To insert a value into a non-associative array, I find this simple function does the trick:

function insert_in_array_pos($array, $pos, $value)
{
  $result = array_merge(array_slice($array, 0 , $pos), array($value), array_slice($array,  $pos));
  return $result;
}

Seems an awful lot simpler than the iterative solutions given above...
aaron dot hawley at uvm dot edu
28-May-2005 02:36
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.
josh at digitalfruition dot com
15-Feb-2005 02:17
Note that array_push() will, as described, return the COUNT of the array after adding a new item, not necessarily the INDEX of that new item:

<?php
$array
= array(3 => 'three', 5 => 'five');

echo
"\$array = ";
print_r($array);
echo
"\n\n";

$to_push = array(1,2,4,);
foreach(
$to_push as $var)
{
   echo
"calling array_push(\$array,$var); retval is ";
   echo
array_push($array,$var);
   echo
"\n";
}

echo
"\$array = ";
print_r($array);
?>

The output of above is:

$array = Array
(
   [3] => three
   [5] => five
)

calling array_push($array,1); retval is 4
calling array_push($array,2); retval is 5
calling array_push($array,4); retval is 6
$array = Array
(
   [3] => three
   [5] => five
   [7] => seven
   [8] => 1
   [9] => 2
   [10] => 4
)

Notice how when array_push($array,1) was called, the new element has a key of 8 but array_push() returns 4.
andrew at cgipro dot com
03-Feb-2005 07:18
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
aron
24-Feb-2004 06:48
The problem with array_push is that it is pass by value.  If you are dealing with objects whose inner state may change at any time, you need a push and pop who return the actual objects, rather than copies of them. 
After some difficulty and board assistance, I have these methods.  I've tested them, and they seem to work fine.

<?php
function push(&$array, &$object){   
  
$array[] =& $object;   
}
function &
pop(&$array){
   return
array_pop($array);
}

// [Test Code]
class TestObject{
   var
$value = 0;
   function
getValue(){
       return
$this->value;
   }
   function
setValue($mixed){
      
$this->value = $mixed;
   }
}
$myarr = array();
$tmp =& new TestObject();
$tmp2 =& new TestObject();
$tmp->setValue(2);
$tmp2->setValue(3);

push($myarr, $tmp);
push($myarr, $tmp2);
$tmp->setValue(4);
$tmp2->setValue(6);
$val = pop($myarr);
print
"popped value: ".$val->getValue()."<br />";

print
"values in internal array: <br />";
foreach (
$myarr as $key=>$value){
   print
"key: $key, object: $value, value: ";
   print 
$value->getValue()."<br />";
}
// [/TestCode]
?>
skiflyer
21-Jan-2004 08:05
However, don't forget that array_push() does more than [], it also performs a count and returns the value.

Modifying your code ever so slightly (see below), this puts array_push in the lead (not suprisingly).  So my conclusion would be that if I care about the number of elements in the array, then I'd use array_push(), if I don't (which is usually the case), then I'd use the [] method.

Results...
[] method: 0.34943199
push method: 0.31505919
difference: -0.03437280

Modified section of code...
$s_test_begin = FullMicroTime();
for($i = 0; $i <= 50000; $i++) { $num_tot = array_push($test2, $i); }
$s_test_end = FullMicroTime();

$f_test_begin = FullMicroTime();
for($i = 0; $i <= 50000; $i++) { $test[] = $i; $num_tot = count($test); }
$f_test_end = FullMicroTime();
ryan at sinn dot org
12-Nov-2003 11:18
You can merge key and value combinations into "variable variable" arrays using {} around the variable name.

Here's an example:

<?php
   $arrayName
= time();
   ${
$arrayName}["mykey"] = "myvalue";

   print
$arrayName.":<br>"
  
print_r($$arrayName);
   print
"<br><br>";
?>
daevid at daevid dot com
14-Mar-2003 10:52
Just to fix and clean up the above example... it should be:

<?php
function addArray(&$array, $key, $val)
{
  
$tempArray = array($key => $val);
  
$array = array_merge ($array, $tempArray);
}
?>

and use this to view them:

<?php
foreach ($myArray as $key=>$val)
{
   echo
"key = ".$key." val = ".$val;
}
?>
daevid at daevid dot com
17-Feb-2003 12:38
Sadly, array_push() does not create an array if the array doesn't exist.  So if you're pushing the first element onto an array, you need to check and create it manually...

<?php
if ( !is_array($myArray) ) $myArray= array();
array_push($myArray, $myElement);
?>
be at my dot net dot sg
16-Feb-2003 04:35
Here's a function to add any key variable into array. this function cannot be use if the key and var set are both numbers.

<?php
function addArray(&$array, $id, $var)
{
  
$tempArray = array($var => $id);
  
$array = array_merge ($array, $tempArray);
}   

$myArray= array ();

addArray($myArray, 1, 'something');
?>

Displaying:

<?php
foreach (array_keys($myArray) as $fields)
{
print
$myArray[$fields];
print
$fields;
}
?>

Result:
1
something
anton at titov dot net
22-Jan-2003 11:23
For the note above: you can use array_splice function to insert a new value (or array) in the middle of array, this will work like your code does:

<?php
$list
= array(
    
"0" => "zero",
    
"1" => "one",
    
"2" => "two",
    
"3" => "three",
    
"4" => "four",
    
"5" => "five",
    
"6" => "six"
);
$value = "New Number Three";
$key = "3";
$new = array_splice($list, $key, 0, $value);
?>
jhall at jadeinternet dot net
17-Dec-2002 11:34
[Editors Note:
See http://www.php.net/array_splice for a function that does the same thing.]

I needed a function to add data to a particular place in an array without loosing any other data in the array. Here it is:

<?php
function insert_into_array($array,$ky,$val)
{
 
$n = $ky;
 foreach(
$array as $key => $value)
   {
    
$backup_array[$key] = $array[$key];
   }
 
$upper_limit = count($array);
 while(
$n <= $upper_limit)
   {
     if(
$n == $ky)
       {
    
$array[$n] = $val;
     echo
$n;
       }
     else
       {
    
$i = $n - "1";
    
$array[$n] = $backup_array[$i];
       }
    
$n++;
   }
 return
$array;
}
?>

So that:

<?php
$list
= array( "0" => "zero",
          
"1" => "one",
          
"2" => "two",
          
"3" => "three",
          
"4" => "four",
          
"5" => "five",
          
"6" => "six");
$value = "New Number Three";
$key = "3";
$new = insert_into_array($list,$key, $value);
?>

Will Return:

$list =
Array
(
   [0] => zero
   [1] => one
   [2] => two
   [3] => three
   [4] => four
   [5] => five
   [6] => six
)

$new=
Array
(
   [0] => zero
   [1] => one
   [2] => two
   [3] => New Number Three
   [4] => three
   [5] => four
   [6] => five
   [7] => six
)
rickf at transpect dot net
06-Nov-2002 09:45
Another associative array sorter. Will handle null arrays, and should correctly handle multidimensionals. Essentially, it pulls all the keys into an array, randomizes that array, then spits out a reconstructed array based on the randomized keys.

I would have used array_keys() instead of the first foreach(), but unfortunately the array returned gets spit back in hash order, not array order. My particular needs required me to have reproducable randomizations based on specific mt_srand() values. For most people who just need a random array output with no reproduction, you can substitute the line beneath.

<?php
function assocArrayShuffle($inarray) {
       if(!
$inarray) return $inarray;
      
$keys = array(); $rkeys = array();
       foreach(
$inarray as $k => $v) $keys[] = $k;
      
// OR... $keys = array_keys();
      
while(count($keys)>0) {
               list(
$k) = array_splice($keys, mt_rand(0, count($keys)-1), 1);
              
$rkeys[] = $k;
       }
       foreach(
$rkeys as $k => $v) $outarray[$v] = $inarray[$v];
       return
$outarray;
}
?>
daniel at nomail dot com
14-Apr-2002 10:17
If you want to use integer keys simply treat it as an 'ordinary' array.

<?php
$user_arr
= array();

$user_id = 4;
$user_name = 'John';
$user_arr[$user_id] = $user_name;

$user_id = 346;
$user_name = 'Steve';
$user_arr[$user_id] = $user_name;

$user_id = 652;
$user_name = 'Maria';
$user_arr[$user_id] = $user_name;
?>

All slots in between the three user IDs will not be allocated and sizeof($user_arr) will return 3 and not 653.
Static
04-Feb-2002 04:19
I noticed that when building a large array, array_push($array, $value) didn't seem to be quite as fast as $array[] = $value. Using the latter would therefore be a useul optimisation if you can guarantee unique keys (e.g. reading from a DB table with an id field).

Static.
bart at framers dot nl
27-Sep-2001 07:16
Array_push also works fine with multidimensional arrays. Just make sure the element is defined as an array first.

<?php
$array
["element"][$element]["element"] = array();
array_push ($array["element"][$element]["element"], "banana");
?>
misc dot anders at feder dot dk
04-Feb-2001 01:43
The $array[] = $var statement differs from array_push($array, $var) in that it can operate on uninitialized variables as well. array_push only works with initialized arrays.