PHP/Data Structure/array

Accessing Array Elements

   <source lang="html4strict">

<? $my_array = array(); $pets = array("A", "B", "C", "D"); $person = array("R", "W", 24, "CA"); $customer = array("first" => "R", "last" => "W", "age" => 24, "state" => "CA");

print "

"$pets[0]".

\n"; print "

$person[2].

\n"; print "

{$customer["age"]}.

\n";

?>

 </source>
   
  

A list of numbers using an array variable

   <source lang="html4strict">

<?php $Inventory = array(1,2,3); print "$Inventory[0]
\n"; print "$Inventory[1]
\n"; print "$Inventory[2]
\n";

print "

An array variable!"; ?> </source>

Arrays

   <source lang="html4strict">

<?

   $myarray = array("Apples", "Oranges", "Pears");
   $size = count($myarray);
   print_r($myarray);

?>

 </source>
   
  

Converting an object to an array will convert properties to elements of the resulting array

   <source lang="html4strict">

<?php class myclass {

   public $name; 
   public $address; 
   private $age; 
   function SetAge($age) { 
       $this->age = $age; 
   } 

} $obj = new myclass; $obj->name = "John"; $obj->address = "Main Street"; $obj->SetAge(47); $arr = (array)$obj; print_r($arr); ?>

 </source>
   
  

Create an array

   <source lang="html4strict">

<? $fruits = array (

   "fruits" => array("a"=>"orange", "b"=>"banana", "c"=>"apple"),
   "numbers" => array(1, 2, 3, 4, 5, 6),
   "holes" => array("first", 5 => "second", "third")

); ?>

 </source>
   
  

Creates an array with keys 0 through 3

   <source lang="html4strict">

<?php

   $myarray = array("a", "b", "c", "d");

?>

 </source>
   
  

Creating arrays with array()

   <source lang="html4strict">

$vegetables = array("corn" => "yellow",

                   "beet" => "red",
                   "carrot" => "orange");

$dinner = array(0 => "S",

               1 => "L",
               2 => "B");

$computers = array("t" => "A",

                  2600 => "B",
                  "A" => "C");

?>

 </source>
   
  

Creating multidimensional arrays with array()

   <source lang="html4strict">

<? $meals = array("breakfast" => array("A","C"),

              "lunch"     => array("B", "E"),
              "snack"     => array("C","F"));

$lunches = array( array("Chicken","Eggplant","Rice"),

                 array("Eggplant","Tofu"));

$flavors = array("Japanese" => array("hot" => "1",

                                    "salty" => "2"),
                "Chinese"  => array("hot" => "3",
                                    "pepper-salty" => "4"));

?>

 </source>
   
  

Creating numeric arrays with array()

   <source lang="html4strict">

<? $dinner = array("A",

               "B",
               "C");

print "I want $dinner[0] and $dinner[1]."; ?>

 </source>
   
  

Demonstrate the Difference Between the Array "+" Operator and a True Array Union

   <source lang="html4strict">

<?php $first = array("e", "h", "r", "j", "b"); $last = array("w", "e", "c"); $plus_union = $last + $first; echo "<p>"; foreach ($plus_union as $v) { echo "{$v} "; }

echo "

\n";

$union = array_unique(array_merge($first, $last));

echo "

"; foreach ($union as $v) { echo "{$v} "; } echo "

\n";

?>

 </source>
   
  

Queue Handling Library

   <source lang="html4strict">

<?php function &queue_initialize() {

   $new = array();
   return $new;

} function queue_destroy(&$queue) {

   unset($queue);

} function queue_enqueue(&$queue, $value) {

   $queue[] = $value;

} function queue_dequeue(&$queue) {

   return array_shift($queue);

} function queue_peek(&$queue) {

   return $queue[0];

} function queue_size(&$queue) {

   return count($queue);

} function queue_rotate(&$queue) {

   $queue[] = array_shift($queue);

} $myqueue =& queue_initialize(); queue_enqueue($myqueue, "Opal"); queue_enqueue($myqueue, "Dolphin"); queue_enqueue($myqueue, "Pelican");

echo "

Queue size is: ", queue_size($myqueue), "

"; echo "

Front of the queue is: ", queue_peek($myqueue), "

";

queue_rotate($myqueue);

echo "

Removed the element at the front of the queue: ", queue_dequeue($myqueue), "

";

queue_destroy($myqueue); ?>

 </source>
   
  

Setting up an associative array is similarly easy

   <source lang="html4strict">

<? $myassocarray = array ("mykey" => "myvalue", "another" => "one"); while ($element = each ($myassocarray)) {

 echo "Key - " . $element["key"] . " and Value - " . $element["value"] . "
"; 

} ?>

 </source>
   
  

Stack Handling Library

   <source lang="html4strict">

<?php function &stack_initialize() {

   $new = array();
   return $new;

} function stack_destroy(&$stack) {

   unset($stack);

} function stack_push(&$stack, $value) {

   $stack[] = $value;

} function stack_pop(&$stack) {

   return array_pop($stack);

} function stack_peek(&$stack) {

   return $stack[count($stack)-1];

} function stack_size(&$stack) {

   return count($stack);

} function stack_swap(&$stack) {

   $n = count($stack);
   if ($n > 1) {
       $second = $stack[$n-2];
       $stack[$n-2] = $stack[$n-1];
       $stack[$n-1] = $second;
   }

} function stack_dup(&$stack) {

   $stack[] = $stack[count($stack)-1];

} $mystack =& stack_initialize(); stack_push($mystack, 73); stack_push($mystack, 74); stack_push($mystack, 5); stack_dup($mystack);

echo "

Stack size is: ", stack_size($mystack), "

"; echo "

Popped off the value: ", stack_pop($mystack), "

";

stack_swap($mystack);

echo "

Current top element is: ", stack_peek($mystack), "

";

stack_destroy($mystack); ?>

 </source>
   
  

Using the array() Function

   <source lang="html4strict">

<?php

   /* Arrays $foo and $bar are equivalent arrays */
   $foo = array("a" => 1, "b" => 2, "c" => 3);
   $bar["a"] = 1;
   $bar["b"] = 2;
   $bar["c"] = 3;

?>

 </source>
   
  

Using the array function to create an array of weekdays

   <source lang="html4strict">

<?php $weekdays = array("Monday",

                 "Tuesday",
                 "Wednesday",
                 "Thursday",
                 "Friday",
                 "Saturday",
                 "Sunday");

?>

 </source>