Array Allocations

This JavaScript program demonstrates various methods for allocating arrays and entries within arrays.

ArrayAllocations.html

<!DOCTYPE html>
<html>
<head>
    <title>XoaX.net's Javascript</title>
</head>
<body>
    <script type="text/javascript" src="ArrayAllocations.js"></script>
</body>
</html>

ArrayAllocations.js

// Create an empty array with no elements in it.
var iaA = [];
// Allocate new entries by assigning them values.
iaA[0] = 4;
iaA[1] = 5;
// Skipped elements are undefined, but are in the array.
iaA[3] = 14;
for(var i = 0; i < iaA.length; ++i) {
  document.writeln("iaA["+ i + "] = " + iaA[i] + "<br />");
}
document.writeln("<br />");


// A simple array initializtion. This array can be extended
var iaB = [40,19,301];
// Add an element to the end of the array
iaB[iaB.length] = 65;
// Add another element via a push
iaB.push(81);
for(var i = 0; i < iaB.length; ++i) {
  document.writeln("iaB["+ i + "] = " + iaB[i] + "<br />");
}
document.writeln("<br />");


// An object that works like an associative array, but can not be indexed.
var saAssoc = [];
saAssoc["Simon"] = "Peter";
saAssoc["Saul"] = "Paul";
for (sName in saAssoc) {
  document.writeln("saAssoc["+ sName + "] = " + saAssoc[sName] + "<br />");
}
document.writeln("saAssoc["+ 0 + "] = " + saAssoc[0] + "<br />");
document.writeln("<br />");


// Use the built-in Array constructor to allocate an empty array.
var iaC = new Array();
// Allocate the entries of the array by pushing them
iaC.push(11);
iaC.push(22);
iaC.push(33);
for(var i = 0; i < iaC.length; ++i) {
  document.writeln("iaC["+ i + "] = " + iaC[i] + "<br />");
}
document.writeln("<br />");


// Use the built-in Array constructor with a set of entries.
var iaD = new Array(9,6,3,7);
for(var i = 0; i < iaD.length; ++i) {
  document.writeln("iaD["+ i + "] = " + iaD[i] + "<br />");
}
document.writeln("<br />");


// Use the built-in Array constructor to allocate an Array of undefined entries.
// Note: This does not create an array with a single entry.
var iaE = new Array(5);
// Fill in the array as you see fit.
iaE[2] = 800;
for(var i = 0; i < iaE.length; ++i) {
  document.writeln("iaE["+ i + "] = " + iaE[i] + "<br />");
}
document.writeln("<br />");

Core JavaScript

Array Allocations

ArrayAllocations.html

ArrayAllocations.js

Output