PHP: array_pad - Manual
(PHP 4, PHP 5, PHP 7, PHP 8)
array_pad — Pad array to the specified length with a value
Description
Parameters
array-
Initial array of values to pad.
length-
New size of the array.
value-
Value to pad if
arrayis less thanlength.
Return Values
Returns a copy of the array padded to size specified
by length with value
value. If length is
positive then the array is padded on the right, if it's negative then
on the left. If the absolute value of length is less
than or equal to the length of the array then no
padding takes place.
Changelog
| Version | Description |
|---|---|
| 8.3.0 | Prior to 8.3, only 1048576 elements could be added at once. Now it is limited only by the maximum size of an array instead. |
Examples
Example #1 array_pad() example
<?php
$input = array(12, 10, 9);$result = array_pad($input, 5, 0);
// result is array(12, 10, 9, 0, 0)
echo join(', ', $result), PHP_EOL;$result = array_pad($input, -7, -1);
// result is array(-1, -1, -1, -1, 12, 10, 9)
echo join(', ', $result), PHP_EOL;$result = array_pad($input, 2, "noop");
// not padded
echo join(', ', $result), PHP_EOL;
?>
See Also
- array_fill() - Fill an array with values
- range() - Create an array containing a range of elements
Found A Problem?
17 years ago
Beware, if you try to pad an associative array using numeric keys, your keys will be re-numbered.
<?php
$a = array('size'=>'large', 'number'=>20, 'color'=>'red');
print_r($a);
print_r(array_pad($a, 5, 'foo'));
// use timestamps as keys
$b = array(1229600459=>'large', 1229604787=>20, 1229609459=>'red');
print_r($b);
print_r(array_pad($b, 5, 'foo'));
?>
yields this:
------------------
Array
(
[size] => large
[number] => 20
[color] => red
)
Array
(
[size] => large
[number] => 20
[color] => red
[0] => foo
[1] => foo
)
Array
(
[1229600459] => large
[1229604787] => 20
[1229609459] => red
)
Array
(
[0] => large
[1] => 20
[2] => red
[3] => foo
[4] => foo
)23 years ago
To daarius - you mean you have...
[2]=>"two"
[3]=>"three"
and you want...
[0]=>"FILLED"
[1]=>"FILLED"
[2]=>"two"
[3]=>"three"
[4]=>"FILLED"
[5]=>"FILLED"
If so, then the following code...
<?php
$array = array(2 => "two", 3 => "three");
$array = array_pad($array, count($array)+2, "FILLED");
$num = -(count($array)+2);
$array = array_pad($array, $num, "FILLED");
print_r($array);
?>
will return:
Array ( [0] => FILLED [1] => FILLED [2] => two [3] => three [4] => FILLED [5] => FILLED )
The ordering should be okay,...23 years ago
to the previous commenter -- if you read the manual entry, you'd see that a negative pad_size will put the pad values at the front of the array.22 years ago
little older, a little wiser.
ksort() will order the array back into its normal order again
so:
<?php
$myArr = array(2 => 'two', 4 => 'four');
$newArr = array_pad(array(), 6, 'FILLED');
$newArr =$myArr+$newArr;
ksort($newArr);
?>
Will give :
Array ( [0] => FILLED [1] => FILLED [2] => two [3] => FILLED [4] => four [5] => FILLED )22 years ago
One way to initialize a 20x20 multidimensional array.
<?php
$a = array();
$b = array();
$b = array_pad($b,20,0);
$a = array_pad($a,20,$b);
?>hk, StrApp Bussiness Solutions ¶
19 years ago
A simple example for array_pad()
the syntax is as follows: array_pad(array(), (+/-)int, value)
where "array" is the array to which the value is to be added,
"(+/-) int" is a value that decides the length of the array(it should be greater than the length of the array.
if its a negative number then the value will be added at the left of the array else it will be added to the right.
"values" denotes the value to be added to the array
lets try an example:
<?php
$digits = array();
$digits[0] = 1;
$digits[1] = 2;
$digits[2] = 3;
$arraypad = array_pad($digits, -4, "0");
print_r($arraypad);
?>
output:
Array ( [0] => 0 [1] => 1 [2] => 2 [3] => 3 )23 years ago
yes that is true. But, if the index of the array is 2=two, 3=three
and i want 4 more keys to be filled. But, not just filled anywhere, but i want to maintain the key index.
so, i would like to have 0=FILLED, 1=FILLED ... 4=FILLED, 5=FILLED
now i got 4 more keys padded with my string.
We can do this "if" we know the missing keys, but if we dont, then it would be nice for array_pad() or perhaps some new function to do this?
obviously we can achive this by looping through the array using array_key_exists(), and if you dont find the key, simply create + fill it.
regards,
Daarius...23 years ago
OR you could do this
<?php
$myArr = array(2 => 'three', 3 => 'four');
$newArr = array_pad(array(), 4, 'FILLED');
$newArr =$myArr+$newArr;
?>
This gives your desired result BUT the ordering is a little wierd, because of the order they were added. Indexes are okay though and that is what you wanted.
print_r($newArr) outputs
Array ( [2] => three [3] => four [0] => FILLED [1] => FILLED )
hope this helps