PHP/Data Structure/array pad

Add new values to the beginning of the array by using a negative value for $size:

 
<?php 
$birds = array("a", "b", "c", "d"); 
$more_birds = array_pad($birds, -6, "some bird"); 
printf("%s", var_export($more_birds, TRUE)); 
?>

An array that is padded from the front

 
<?
    $weights = array (1, 3, 5, 10, 15, 25, 50);
    $weights = array_pad($weights, -10, 100);
    print_r($weights);
?>

array_pad 1

 
<?php
  $birds = array("parrot", "magpie", "lorakeet", "cuckoo");
  $more_birds = array_pad($birds, 6, "some bird");
  printf("<p>More birds:</p><pre>%s</pre>\n", var_export($more_birds, TRUE));
?>

array_pad 2

 
<?php
  $birds = array("parrot", "magpie", "lorakeet", "cuckoo");
  $more_birds = array_pad($birds, -6, "some bird");
  printf("<p>More birds:</p><pre>%s</pre>\n", var_export($more_birds, TRUE));
?>

array_pad 3

 
<?php
  $dogs = array("A" => "AA", "Bud" => "BB","C" => "D");
  $pups = array_pad($dogs, 6, "mutt");
  printf("<p>Pups:</p><pre>%s</pre>\n", var_export($pups, TRUE));
  $pups = array_pad($dogs, -6, "mutt");
  printf("<p>Pups:</p><pre>%s</pre>\n", var_export($pups, TRUE));
  printf("<p>Dogs:</p><pre>%s</pre>\n", var_export($dogs, TRUE));
?>

array_pad() function expands an array to a precise size, padding it with a default value.

 
//Its syntax is: array array_pad(array array, int pad_size, mixed pad_value);
pad_size specifies the new length of the array. 
pad_value parameter specifies the default value. 
If pad_size is positive, then the array will be padded to the right; 
If pad_size is negative, the array will be padded to the left.
If the absolute value of pad_size is less than or equal to the length of the array, then no action will be taken.
<?
    $weights = array (1, 3, 5, 10, 15);
    $weights = array_pad($weights, 10, 100);
    print_r($weights);
?>

Pad array to the specified length with a value

 
<?
$input = array (12, 10, 9);
$result = array_pad ($input, 5, 0);
$result = array_pad ($input, -7, -1);
$result = array_pad ($input, 2, "noop");
?>

Setting an Array"s Size: array array_pad(array $input, int $size, mixed $value)

 
<?php 
$birds = array("a", "b", "c", "d"); 
$more_birds = array_pad($birds, 6, "some bird"); 
printf("Birds:%s", var_export($birds, TRUE)); 
printf("More birds:%s", var_export($more_birds, TRUE)); 
?>

Using array_pad() with associative arrays

 
<?php 
$dogs = array("A" => "C", "B" => "D", "X" => "Z"); 
$pups = array_pad($dogs, 5, "mutt"); 
printf("right padding:%s", var_export($pups, TRUE)); 
$pups = array_pad($dogs, -5, "mutt"); 
printf("left padding:%s", var_export($pups, TRUE)); 
printf("Dogs:%s", var_export($dogs, TRUE)); 
?>