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
)
array_pad
(PHP 4, PHP 5, PHP 7, PHP 8)
array_pad — 指定長、指定した値で配列を埋める
説明
array_pad() は、length
で指定した長さになるように値 value で埋めて
array のコピーを返します。
length が正の場合、配列の右側が埋められます。
負の場合、配列の左側が埋められます。
length の絶対値が
array の長さ以下の場合、埋める処理は行われません。
パラメータ
-
array -
値を埋めるもととなる配列。
-
length -
新しい配列のサイズ。
-
value -
arrayがlengthより小さいときに、 埋めるために使用する値。
戻り値
length
で指定した長さになるように値 value で埋めて
array のコピーを返します。
length が正の場合、配列の右側が埋められます。
負の場合、配列の左側が埋められます。
length の絶対値が
array の長さ以下の場合、埋める処理は行われません。
変更履歴
| バージョン | 説明 |
|---|---|
| 8.3.0 | PHP 8.3 より前のバージョンでは、 一度に 1048576 個の要素しか追加できませんでした。 このバージョンからは、制限は配列の最大サイズのみになりました。 |
例
例1 array_pad() の例
<?php
$input = array(12, 10, 9);
$result = array_pad($input, 5, 0);
// 結果は、array(12, 10, 9, 0, 0) です。
$result = array_pad($input, -7, -1);
// 結果は、array(-1, -1, -1, -1, 12, 10, 9) です。
$result = array_pad($input, 2, "noop");
// 埋める処理は行われません。
?>
add a note
User Contributed Notes 11 notes
tugla ¶
16 years ago
goffrie at sympatico dot ca ¶
21 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,...
scott*hurring.com ¶
22 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.
mwwaygoo at hotmail dot com ¶
20 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 )
Anonymous ¶
20 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 ¶
17 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 )
daarius at hotmail dot com ¶
22 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...
mwwaygoo at hotmail dot com ¶
22 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
oaev at mail dot ru ¶
20 years ago
Easy way to get an array contains 5 random numbers from 0 to 9:
$rand_arr = array_rand( array_pad( array(), 10, 1 ), 5 );
slava-san at mail dot ru ¶
11 years ago
// insert element to array
function array_insert(&$arr, $pos, $new_el=null) {
$arraypad = array_pad($arr, count($arr)+1, 0);
for ($i=count($arr)-1; $i>=$pos; $i--) {
$arr[$i+1] = $arr[$i];
if ($i == $pos) {
$arr[$i] = $new_el;
}
}
}
$digits = array();
$digits[0] = 0;
$digits[1] = 1;
$digits[2] = 2;
$digits[3] = 3;
$digits[4] = 4;
$digits[5] = 5;
echo "was: "; var_dump($digits);
array_insert($digits, 3, 100);
echo "new: "; var_dump($digits);
sonu50imedbvu at gmail dot com(Sonu Jaiswal) ¶
13 years ago
Just an info about the value of "$pad_size" ,
If we set the value of "$pad_size" from -3 to 3,
It will produce the output like:
<?php
$result = array_pad($input, -3, "noop");
//result is array(12, 10, 9)
$result = array_pad($input, 3, "noop");
//result is array(12, 10, 9)
?>
means array will remain the same.
