Mega Code Archive
Array Utility functions
<![CDATA[
/*
JavaScript Application Cookbook
By Jerry Bradenbaugh
Publisher: O'Reilly
Series: Cookbooks
ISBN: 1-56592-577-7
*/
<HTML>
<HEAD>
<TITLE>arrays.js Example</TITLE>
<SCRIPT LANGUAGE="JavaScript1.2">
// arrays.js
// Add up the values of all the elements, then
// divide that sum by the number of elements
function avg(arrObj) {
var sum = 0;
for (var i = 0; i < arrObj.length; i++) {
sum += arrObj[i];
}
return (sum / i);
}
// Iterate through the elements,
// and return the highest
function high(arrObj) {
var highest = arrObj[0];
for (var i = 1; i < arrObj.length; i++) {
highest = (arrObj[i] > highest ? arrObj[i] : highest);
}
return (highest);
}
// Iterate through the elements,
// and return the lowest
function low(arrObj) {
var lowest = arrObj[0];
for (var i = 1; i < arrObj.length; i++) {
lowest = (arrObj[i] < lowest ? arrObj[i] : lowest);
}
return (lowest);
}
// Iterate through the elements, amd perform
// a string replacement on each
function jsGrep(arrObj, regexp, subStr) {
for (var i = 0; i < arrObj.length; i++) {
arrObj[i] = arrObj[i].replace(regexp, subStr);
}
return arrObj;
}
// This function returns a copy of an array object
// with the last element removed
function truncate(arrObj) {
arrObj.length = arrObj.length - 1;
return arrObj;
}
// This function returns a copy of an array
// object with the first element removed
function shrink(arrObj) {
var tempArray = new Array();
for(var p = 1; p < arrObj.length; p++) {
tempArray[p - 1] = arrObj[p];
}
return tempArray;
}
// This function returns a copy of an array
// object with the elements of another array
// object added beginning from a specified index.
function integrate(arrObj, elemArray, startIndex) {
startIndex = (parseInt(Math.abs(startIndex)) < arrObj.length ? parseInt(Math.abs(startIndex)) : arrObj.length);
var tempArray = new Array();
for( var p = 0; p < startIndex; p++) {
tempArray[p] = arrObj[p];
}
for( var q = startIndex; q < startIndex + elemArray.length; q++) {
tempArray[q] = elemArray[q - startIndex];
}
for( var r = startIndex + elemArray.length; r < (arrObj.length + elemArray.length); r++) {
tempArray[r] = arrObj[r - elemArray.length];
}
return tempArray;
}
// This function returns an array reordered according to a multiple
// passed in by the user. The defualt is 1.
function reorganize(formObj, stepUp) {
stepUp = (Math.abs(parseInt(stepUp)) > 0 ? Math.abs(parseInt(stepUp)) : 1);
var nextRound = 1;
var idx = 0;
var tempArray = new Array();
for (var i = 0; i < formObj.length; i++) {
tempArray[i] = formObj[idx];
if (idx + stepUp >= formObj.length) {
idx = nextRound;
nextRound++;
}
else {
idx += stepUp;
}
}
return tempArray;
}
</SCRIPT>
</HEAD>
<BODY>
<SCRIPT LANGUAGE="JavaScript1.2">
<!--
var someArray = new Array(1,2,3,.1098,5,2,3.456,1324.55,-0.76,45,3,47.234,.00060,65.7,1,3,2,4,55);
var grepExample = new Array('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday');
document.write("<B>Original Array: " + someArray + "</B><BR>" +
"Average: " + avg(someArray) + "<BR>" +
"Lowest: " + low(someArray) + "<BR>" +
"Highest: " + high(someArray) + "<BR>" +
"Truncate by 1: " + truncate(someArray) + "<BR>" +
"Shrink by 1: " + shrink(someArray) + "<BR>" +
"Reorganize(by 4): " + reorganize(someArray, 4) + "<BR>" +
"Integrate ('An element', 'Another one', and 'One more', at index 5): " +
integrate(someArray, new Array('An element', 'Another one', 'One more'), 5) + "<BR><BR>" +
"<B>Original grepExample Array: " + grepExample + "</B><BR> jsGrep(grepExample, /day/, \'day Night\'): " +
jsGrep(grepExample, /day/, 'day Night') + "<BR>");
//-->
</SCRIPT>
</BODY>
</HTML>
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