Using Arrays As Objects?
Jul 4, 2011
"When we combine FUNCTIONS with OBJECTS we get METHODS". Then he creates an empty ARRAY:
var a = [];
then he uses the "push() method" to add elements to the array.
a.push(1,2,3);
uh, methods are for *objects* right? Yet he is using them on an ARRAY.how an array can magically becomes an object that is manipulated by a "method"?I mean, the array is still an array, no? It never actually becomes an object, right? Yet we still use a *method* to manipulate it. See my conceptual quandry?
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Jun 20, 2007
I recently had a problem where I needed to build up an array of strings, that would be join()ed into a string when the array building was complete. however, each value could only be in the array once.
This was a problem for a few reasons. Once a value has gone into an array the only way to check for it that works cross-platform is to scan the array looking for the value. FireFox has the every() and some() functions but they don't work in anything else.
Using an object to simulate an assocaiative array would allow me to avoid this problem by storing key/values with the keys having the same value as the value I was storing. I could then use the (a in b) construct to check that I had not already added a value.
However, array type methods won't work with objects, so I had no access to size () or join () meaning I'd have to manually build the string by iterating over the object.
My solution was to use an array object, but to store the provided data i nboth the array proper and as a property of the array object.
var myArray = new Array;
function addVal (val)
{
if (!(val in myArray))
{
myArray [val] = 1;
myArray.push (val);
}
}
addVal ('one');
addVal ('two');
addVal ('three');
addVal ('one');
addVal ('two');
addVal ('three');
console.log (myArray.length);
console.log (myArray.join (', '));
This approach does use up more memory but it does give me the advantages of both arrays and objects for little extra work. (if you don't have FireBug then replace console.log with alert)
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Oct 28, 2003
I am dabbling with objects and have successfully created an object with various properties, one of which is an Array, and all is fine. the Question I have is can I make an Array of objects? I have the following object:
dataSeries.Type = value
dataSeries.Name = value
dataSeries.dataPoints[n] = Array of values
dataSeries.color = value
What I would like to do is have an Array of multiple objects supposedly like:
dataSeries[0].Type = value
dataSeries[1].Name = value
dataSeries[2].dataPoints[n] = Array of values
dataSeries[3].color = value
Is this possible?
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Sep 16, 2010
I am trying to return a JSON string from a server with a list of locations. I want to populate a div with checkboxes and the names of the locations.This is the JSON string I am currently working with:
Code:
[{"loccode":2,"locdesc":"Atlanta"},
{"loccode":1,"locdesc":"Charlotte"},
{"loccode":0,"locdesc":"NA"},
{"loccode":3,"locdesc":"Test1A"}]
I have a similarly formed data definition that is hard coded in the javascript for permissions that looks like this:
Code:
var prm = [
{"id":110,"idtext":"110","prmdesc":"Users"},
{"id":130,"idtext":"130","prmdesc":"Forms"},
[code]....
When i run that bit of code it displays Test1A and that is all.I am certain I am missing something basic, but I have not been able to figure out what it is.
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Apr 10, 2011
I'm have some javascript objects with arrays that should be transferred as php array.Its posted by ajax httpRequest.How can I return php array, from the javascript?
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Apr 24, 2011
I am really hoping someone is willing to take the time to read this post and take a minute to take a look at my code. What is happening is there are some matches for a script I made and then an area for segments during an event. If you notice on the segment part of the form is that there is a dropdown that asks for where in the event that segment needs to go. With the Introduction or the different numbered matches. What I need to happen for a subArray I need it to take the introduction, all the matches, and all the segments and order them accordingly. With the introduction first, the matches in order based off there match number and then the segments in between the introduction or matches based off the user's input.
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Feb 10, 2011
Trying to figure out OO programming for JavaScript and I'm totally lost.
Here's what I'm trying to do:
I'm posting search data to a PHP form to run a query on a database.
The structure is sort of like this:
So I'm thinking I need to create search objects or arrays. Initially, I thought I could do something like this:
Code:
This doesn't seem to work. It says object not defined whenever I try to do something.
I've also tried creating a JSON object like this:
Code:
This will allow me retrieve the data like I want to:
Code:
The problem is I can't figure out how to add data to the JSON object without manually typing it in. I need to be able to loop through form elements on my HTML page and set them to these variables. I'm using jQuery and doing something like this:
Code:
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Apr 17, 2011
Is there a way in Javascript or Jquery to return an array of all objects underneath a certain point, ie. the mouse position. Basically, I have a series of images which link to various web pages but I have a large semi transparent image positioned over the top of the other images. I want to find the href of the background image that the mouse pointer clicks over.
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Sep 5, 2009
Is there a better way to extend object with internal objects?
$.fn.bestShow = function(s) {
var d = {
width: 0,
height: 0,
order: "numeric",
orderBy: "",
[Code]...
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Jul 23, 2005
I've noticed that IE apparently has a horrible implementation of the
array object, since traversing one with as few as 1000 items it tends
to pop up a dialog informing the user that the script is taking too
long. I tried splitting the array into a 10x100 two-dimensional array
as well as changing the array to a linked list, but neither improved
the code's efficiency sufficiently. Can anyone suggest methods for
optimizing array efficiency, or some other workaround for yet another
one of Bill Gates' blunders?
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Jul 23, 2005
I have a web document created by a script and instead of going back to
the db I choose to either create an array to iterate through or xml to
parse through.
So, my question is: What are the trade offs between using an array to
load data from or an xml structure?
My array would look like:
myarray = [[],[],[],[]]
My xml like:
<xml>
<data>
<a></a><b></b>
</data>
</xml>
I would use js to iterate or getElementByTagName to find data. I am thinking the page would load faster using xml, and then the user may not even use that functionality. In all cases I have to load the array to memory.
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May 23, 2007
I am with XHTML and CSS as much do I have to learn in JavaScript programming. I’m just beginning to understand and modify the DOM and I ran into something that I couldn’t find a solution for after some extensive search. I have this function:
if(document.getElementById && document.createElement) {
function addflags() {
var children = document.getElementById('pagelist').childNodes;
for(var i = 0; i < children.length; i++) {
children[0].className = 'bulgaria'
children[1].className = 'england'
children[2].className = 'italy'
children[3].className = 'sweden'
}
}
window.
}
The XHTML is an unordered list with 4 list items and sub lists in those list items (plus links in each li) and I want to add a country flag (set as background image in the CSS) to the direct children of the ul (the first level list items).
Now I discovered that Firefox is only reacting to odd array numbers, i.e. children[1], 3, 5, and 7 (the even numbers have "no properties") while IE is applying the classes correctly(?) as intended above (0,1,2,3).
At which point did I go wrong? Sorry if this is a real stupid question but I’m pretty new in this field and my researches didn’t bring any acceptable results.
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Oct 5, 2005
Is what I'm doing the right approach to creating an array of arrays? I have an external datafile with several employees' records. They are stored in an array with each element of the array being the complete employee record, ie: name, date of hire, etc., etc. These attributes are delimited by a :. I'm trying to separate these attributes while keeping the original array intact. That way I can access these attributes and validate whether or not an instance of the employee object will occur. There are too many records to create this from the start, so I'm trying to implement a for loop to do it for me. This is what I tried: datafile is the name of the original array of employees. emp is the array I'm trying to create .
for(var i=0;i<datafile.length;i++){
var emp = datafile[i].split(":");
//document.writeln(emp.length+"<br>");
/document.writeln(datafile[i]+"<br>");
}
//document.writeln(datafile[0]+"<br>");
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Jul 23, 2005
How do I set this to "disabled":
<select name="awards[]" multiple size="6">
<option value="1">Award 1</option>
<option value="2">Award 2</option>
<option value="3">Award 3</option>
<option value="4">Award 4</option>
</select>
I don't know how many options there will be as they are fed from a DB.
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Nov 23, 2005
Anybody got any suggestions about using two arrays. First i need to
ask the user their name and if their require a seat between 1and 5 or
between 6 and 10. I need to assign this information in two arrays.
Any suggestions. I have been working on this so far.
<script type="text/javascript">
var theArray = new Array(10);
//var sizeOfArray = parseInt(prompt("How many items will the array
have?", ""));
for(i=0; i<10; i++)
{
theArray[i] = prompt( "Please enter your name");
}
for(i=0; i<theArray.length; i++)
{
document.writeln( "theArray[" + i + " ] = " + theArray[i] + "<br />");
}
</script>
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Sep 12, 2006
I want to make algorithms that take selections from arrays and put them together in new ways. here is a simple array I set up for notes of a piano keyboard: Code:
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Mar 6, 2007
Safari and FF seem to allow this:
var wiggy = "ABCD";
ch = wiggy[2]; // ch will contain the character 'C'
however my JS book seems to insist that I do this:
ch = wiggy.charAt(2);
and indeed doesn't appear to mention the first method at all.
Since for my particular purpose I want to treat the string as an array
of single characters, I prefer the first method rather than the second.
Is there any reason not to pursue this approach?
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Jul 20, 2005
Any neat way to copy a snapshot of one array to another?
A normal assignment results in the second array pointing to the first,
with changes to either array affecting both.
As a trivial example:
var a=new Array();
a[0]="zero";
var b=a;
b[1]="one";
alert("a="+a.join("*")+String.fromCharCode(10)+"b="+b.join("*"));
.... this results in a and b being identical two-element arrays.
Is there any easy way to set array (b) to be a copy of (a) BY VALUE -
ie using the contents of (a) as they were at the moment of assignment,
but leaving the two arrays separate so that subsequent changes to one
array does not affect the other?
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Jul 20, 2005
looking for a way to pass an array to a function.
====================================
<script>
function myfunction(arrayname)
{
document.write("blablabla"+ arrayname[1] +"blablabla");
}
</script>
<html stuff>
<script>
arrayname = new Array("what", "is", "wrong");
myfunction(arrayname);
</script>
====================================
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May 18, 2011
I'm a newbie of JS and don't know if I have got the right terms in my question. I want to lowercase all the arrays:
<script>
var txt = [
["Cats","Dogs","Rabbits"],
["Fish","Bones","Carrots"]
]
document.write(txt[0][1] + " love eating " + txt[1][1]);
[Code]...
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Dec 16, 2011
I have 2 arrays and I would like to compare the 2 arrays.If an element in array 1 is NOT in array 2 then I would like to display that element. In this case, I should only display the letter "c" but it doesn't work and I don't know why?
Here's my code:
<html><head>
<script type="text/javascript">
function getValue(id){
[code]....
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Jul 16, 2010
for example if I have two arrys
arr1[10,20,30]
arr2[40,50,60]
how to merge them to get arr1[10,20,30,40,50,60]
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Jul 12, 2005
Have an array l am building up during end user selections. There is an option to clear all selections, how do l then clear the array?
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Jul 17, 2006
I have been working on this for the last couple days and have made a lot of headway, but am still stuck on a spot. I have a group of checkboxes on my form that allow the user to select which items apply. I want to verify that at least one checkbox in each group has been selected before allowing them to continue. PHP requires the naming of the arrays to include the [] but jsp (for verification) doesn't like it. I read about and used the .elements method to overcome part of that problem so my for loop is now executing for the number of items in my group:
for (var i=0; i<document.form1.elements['dining_out1[]'].length; i++)
however my if statement won't execute:
if (document.form1.elements['dining_out1[i]'].checked)
even if I have checked ALL checkboxes. I have tried all the different methods I can think of to test for a checked value on each item in the array, but I can't quite figure out what I am missing.
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Aug 17, 2006
How do you change array values based on if..then statements?
if(radioObj[0].checked == true) {
nPrice = new Array ("106.99" , "86.99" , "115.99" , "319.99" )
}
if(radioObj[1].checked == true) {
nPrice = new Array ("89.99" , "74.99" , "102.99" , "239.99" )
}
Specifically, what is wrong with that above?
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Jun 12, 2007
Basically on the load of a page I am making an ajax call that returns a string with integers seperated by commas. I have verified that the returns from the ajax call are working correctly, but then I am trying to take that string, break it into an array, and use the values in that array to use setTimeout and call the function at those intervals.
//Create our array outside of a function so it's available
var wait_time = new Array();
//function that handles the ajax return
function process_wait_time_return(str)
{
wait_time = str.responseText.split(',');
update_current_show(0, wait_time);
}
//Function that changes the div html with new information
function update_current_show(array_index, wait_time)
{
$("currently_playing").innerHTML = array_index;
var next_index = array_index + 1;
setTimeout('update_current_show(next_index, wait_time)', 3);
}
This is on a test page, so for testing purposes I'm just updating the div with the current array index to verify it's cycling through the array, which it's not.
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