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array_pad — 用值将数组填补到指定长度
$input
, int $pad_size
, mixed $pad_value
) array_pad() 返回
input
的一个拷贝,并用
pad_value
将其填补到
pad_size
指定的长度。如果
pad_size
为正,则填补到数组的右侧,如果为负则从左侧开始填补。如果
pad_size
的绝对值小于或等于
input
数组的长度则没有任何填补。有可能一次最多填补
1048576 个单元。
input
需要被填充的原始数组。
pad_size
新数组的长度。
pad_value
将被填充的值,只有在 input
的现有长度小于
pad_size
的长度时才有效。
返回 input
用 pad_value
填充到 pad_size
指定的长度之后的一个副本。
如果 pad_size
为正,则填补到数组的右侧,如果为负则从左侧开始填补。
如果 pad_size
的绝对值小于或等于 input
数组的长度则没有任何填补。
Example #1 array_pad() 例子
<?php
$input = array( 12 , 10 , 9 );
$result = array_pad ( $input , 5 , 0 );
// result is array(12, 10, 9, 0, 0)
$result = array_pad ( $input , - 7 , - 1 );
// result is array(-1, -1, -1, -1, 12, 10, 9)
$result = array_pad ( $input , 2 , "noop" );
// not padded
?>
[#1] slava-san at mail dot ru [2013-07-06 10:58:06]
// insert element to array
function array_insert(&$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);
[#2] sonu50imedbvu at gmail dot com(Sonu Jaiswal) [2011-01-12 00:53:01]
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.
[#3] tugla [2008-12-18 09:23:35]
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
)
[#4] hk, StrApp Bussiness Solutions [2007-01-08 02:15:19]
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 )
[#5] oaev at mail dot ru [2004-10-21 23:48:21]
Easy way to get an array contains 5 random numbers from 0 to 9:
$rand_arr = array_rand( array_pad( array(), 10, 1 ), 5 );
[#6] [2004-02-28 21:00:40]
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);
?>
[#7] mwwaygoo at hotmail dot com [2004-01-16 08:02:44]
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 )
[#8] goffrie at sympatico dot ca [2003-03-23 17:06:54]
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,...
[#9] mwwaygoo at hotmail dot com [2002-09-19 09:39:38]
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
[#10] daarius at hotmail dot com [2002-07-23 07:36:33]
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...
[#11] scott*hurring.com [2002-07-19 16:20:08]
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.