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array_push (PHP 4, PHP 5) array_push --
Push one or more elements onto the end of array
Descriptionint array_push ( array &array, mixed var [, mixed ...] )
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:
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<?php
$array[] = $var;
?>
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repeated for each var.
Returns the new number of elements in the array.
Example 1. array_push() example |
<?php
$stack = array("orange", "banana");
array_push($stack, "apple", "raspberry");
print_r($stack);
?>
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This example would result in $stack having
the following elements:
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Array
(
[0] => orange
[1] => banana
[2] => apple
[3] => raspberry
)
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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.
See also array_pop(),
array_shift(), and
array_unshift().
User Contributed Notes
array_push
josh at digitalfruition dot com
14-Feb-2005 12:17
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
02-Feb-2005 05:18
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 04:48
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);
}
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 />";
}
?>
skiflyer
20-Jan-2004 06:05
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();
daijoubuNOSP at Mvideotron dot ca
28-Nov-2003 10:44
If you're only pushing one element, $array[] seems to be a bit faster
<?php
$array = array();
array_push ($array, 'foo');
?>
VS
<?php
$array[] = 'foo';
?>
ryan at sinn dot org
11-Nov-2003 09:18
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
13-Mar-2003 08:52
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
16-Feb-2003 10:38
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, $myElement);
?>
be at my dot net dot sg
16-Feb-2003 02:35
Here's a function to add any key variable into array. this function cannot be use if the key and var set are both numbers.
<?php
function addArray(&$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 09:23
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, $value);
?>
jhall at jadeinternet dot net
16-Dec-2002 09:34
[Editors Note:
See http://www.php.net/array_splice for a function that does the same thing.]
I needed a function to add data to a particular place in an array without loosing any other data in the array. Here it is:
<?php
function insert_into_array($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
)
$new=
Array
(
[0] => zero
[1] => one
[2] => two
[3] => New Number Three
[4] => three
[5] => four
[6] => five
[7] => six
)
rickf at transpect dot net
05-Nov-2002 07:45
Another associative array sorter. Will handle null arrays, and should correctly handle multidimensionals. Essentially, it pulls all the keys into an array, randomizes that array, then spits out a reconstructed array based on the randomized keys.
I would have used array_keys() instead of the first foreach(), but unfortunately the array returned gets spit back in hash order, not array order. My particular needs required me to have reproducable randomizations based on specific mt_srand() values. For most people who just need a random array output with no reproduction, you can substitute the line beneath.
<?php
function assocArrayShuffle($inarray) {
if(!$inarray) return $inarray;
$keys = array(); $rkeys = array();
foreach($inarray as $k => $v) $keys[] = $k;
while(count($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
13-Apr-2002 09:17
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 02:19
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 06:16
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
03-Feb-2001 11:43
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.
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array_product