array_pad

说明

array array_pad ( array 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，则数组被填补到右侧，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。

例子 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 ?>

参见 array_fill() 和 range()。

add a note User Contributed Notes

oaev at mail dot ru
22-Oct-2004 02:48


Easy way to get an array contains 5 random numbers from 0 to 9:



$rand_arr = array_rand( array_pad( array(), 10, 1 ), 5 );

29-Feb-2004 01:00


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);


?>

mwwaygoo at hotmail dot com
17-Jan-2004 12:02


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 )

goffrie at sympatico dot ca
24-Mar-2003 09:06


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,...

mwwaygoo at hotmail dot com
20-Sep-2002 12:39


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

daarius at hotmail dot com
23-Jul-2002 10:36


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...

scott*hurring.com
20-Jul-2002 07:20


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.

ethanhunt314 at hotmail dot com
10-Dec-2000 08:25


This is useful when using next() and prev() function in a while loop to traverse an array. 





For example the following code will only output up to 8.





<?php


$test[] = "1";


$test[] = "2";


$test[] = "3";


$test[] = "4";


$test[] = "5";


$test[] = "6";


$test[] = "7";


$test[] = "8";


$test[] = "9";


$test[] = "10";


$test[] = " ";


$test[] = " ";


$test[] = " ";





$count = count($test);





while($i < $count) {





$now = current($test);


echo "<p>$now</p>";





next($test);


next($test);


next($test);


prev($test);


prev($test);


prev($test);








$i++;


next($test);


}


?>





But if you use:


$test = array_pad($test, 13, " ");





you will get all of your output.

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