Associative Arrays in ActionScript

Actionscript Course

Associative arrays use strings in place of index numbers, to associate the value of the elements. These indexes must be specified by the programmer.
- The syntax to create an associative array is:

var array_name:Array = new Array();
 array_name['index1'] = value1;
 array_name['index2'] = value2;
 array_name['index3'] = value3;

- You can add as many elements as you want.
- You can use either single or double quotes for "index".

You can access or change the value of a specific element of an associative array the same as with a numeric indexed array, using its index:   array_name['index'].

• The elements of an associative array can also be accessed with the dot (.) operator:   array_name.index   (like the proprietes of an object).

Here's an example in which we apply both methods:

// associative array, with 3 elements
var m_ar:Array = new Array();
 m_ar['site'] = 'coursesweb.net';
 m_ar['course'] = 'Adobe Flash';
 m_ar['tutorials'] = 'ActionScript';

// Access the element with index 'site'
trace(m_ar['site']);         // coursesweb.net

// Access another element, using the dot (.) operator
trace(m_ar.course);           // Adobe Flash

Traverse associative Arrays

You can traverse an associative array with the for..in, or for each..in loop.

Example with for..in

// associative array, with 3 elements
var m_ar:Array = new Array();
 m_ar['site'] = 'coursesweb.net';
 m_ar['course'] = 'Adobe Flash';
 m_ar['tutorials'] = 'ActionScript';

// create a "for..in" loop to traverse the "m_ar" array
for(var key:String in m_ar)
{
  // displays in Output the index and the value of the current item
  trace('Index='+ key+ ' - value='+ m_ar[key]);

  // You can execute any operations with "key" si "m_ar[key]"
}

- key is a variable which stores the "index" of the current element (you can use any name for the variable).
In Output will display:

Example with for each..in

// associative array, with 3 elements
var m_ar:Array = new Array();
 m_ar['site'] = 'coursesweb.net';
 m_ar['course'] = 'Adobe Flash';
 m_ar['tutorials'] = 'ActionScript';

// create a "for each..in" loop to traverse the "m_ar" array
for each(var elm in m_ar)
{
  // displays in Output the value of the current item (stored in elm)
  trace('valE - '+ elm);

  // You can execute any operations with "elm"
}

• Notice the diferences between "for..in" and "for each..in". The "for each..in" loop doesn't get the index of the element. The "elm" store the element itself.
In Output will display:

<p>Web development courses: <em>CoursesWeb.net</em></p>

h3 {
  padding: 2px 0.2em;
}

// gets first Div with class="cls", and shows its content
var elm = document.querySelector("div.cls");
alert(elm.innerHTML);

if(isset($_POST["field"])) {
  echo $_POST["field"];
}