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JavaScript Clearing Array Value

I have an array of arrays in JavaScript that I'm storing some values in, and I'm attempting to find a way to clear the value within that array when the user removes the specified control from the page, however I'm not finding a good way to do this and anything I try doesn't seem to be working.
What is the best method for clearing the value in the array? I'd prefer the value to be null so that it's skipped when I iterate over the array later on.
I've tried to do MyArray[id][subid] = '' but that still is technically a value. I've also tried to do MyArray[id][subid].length = 0 but that doesn't seem to do anything either. Trying to grab the index and splice it from the array returns a -1 and therefore doesn't work either.
var MyArray;
window.onload = function(){
MyArray = new Array();
}
function EditValuesAdd(){
var Input = document.getElementById('Values-Input').value;
var ID = document.getElementById('FID').value;
var ValueID = ControlID(); // generate GUID
if (!MyArray[ID]) MyArray[ID] = new Array();
MyArray[ID][ValueID] = Input;
document.getElementById('Values').innerHTML += '<a href="#" id="FV-' + ValueID + '" onclick="EditValuesRemove(this.id)"/><br id="V-' + ValueID + '"/>';
}
function EditValuesRemove(id)
{
var ID = document.getElementById('FID').value;
document.getElementById(id).remove();
document.getElementById(id.replace('FV-', 'V-')).remove();
MyArray[ID][id.replace('FV-', '')] = '';
}
I've also tried to do an index of and then splice it from the underlying array but the index always returns -1.
var Index = MyArray[ID].indexOf(id.replace('FV-', ''));
MyArray[ID].splice(Index, 1);
Setting the length to zero has no effect either.
MyArray[ID][id.replace('FV-', '')].length = 0;
I would expect that one of the methods above would clear out the value and make it null so that it is skipped later on but all of the methods I've found and tried so far leave some non-null value.

What you need is an object (a Map), not an array (a list).
Here's a basic idea of how to do it :
MyArray = {};
....
if (!MyArray[ID]) MyArray[ID] = {}
MyArray[ID][ValueID] = Input;
...
delete MyArray[ID][id.replace('FV-', '')];
Check here for more information : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object

In the end I used an array of objects MyArray = [] and then using splice/findindex to remove it from the array:
function RemoveItem(id)
{
var Index = MyArray.findIndex(a => a.ID == id.replace('FV-', ''));
MyArray.splice(Index, 1);
document.getElementById(id).remove();
document.getElementById('FVB-' + id.replace('FV-', '')).remove();
}
It doesn't solve the actual question asked but I don't know if there really is an answer since I was using arrays in the wrong manner. Hopefully this at least points someone else in the right direction when dealing with arrays and objects.

Pushing object to array results in same value

I have the following javascript code that does not work as I would expect it to. I have a list of checkboxes of which two of the items are "TestDuration" and "AssessmentScores". I'm trying to iterate through the list (which works fine) and have it add the values that are checked to the array.
var SAIndex = 0;
var SSIndex = 0;
var ScoresIndex = 0;
var SubAssessments = [];
var SubAssessmentScores = [];
//Get to the container element
var SSList = document.getElementById("islSubAssessmentScore_container");
//turn it into an array of the checkbox inputs
SSList = SSList.getElementsByTagName("input");
//create a temporary object to store my values
var tempPair = new Object();
//iterate through the checkbox lists
for(var i = 1; i < SSList.length;i++)
{
//if the value is checked add it to the array
if (SSList[i].checked)
{
var P = SubAssessments[SAIndex];
var V = SSList[i].value;
//tempPair.Parent = SubAssessments[SAIndex];
tempPair.Parent = P;
//tempPair.Value = SSList[i].value;
tempPair.Value = V;
//show me the values as they exist on the page
alert(tempPair.Parent + "|" + tempPair.Value);
SubAssessmentScores.push(tempPair);
//show me the values I just added to the array
alert(SubAssessmentScores.length-1 + "|" + SubAssessmentScores[SubAssessmentScores.length-1].Parent + "|" + SubAssessmentScores[SubAssessmentScores.length-1].Value);
//uncheck the values so when I refresh that section of the page the list is empty
SSList[i].checked = false;
}
}
//output the list of objects I just created
for (i = 0;i < SubAssessmentScores.length;i++)
alert(i + "|" + SubAssessmentScores[i].Parent + "|" + SubAssessmentScores[i].Value)
Now what happens is that when I iterate through the list I get the following alerts:
-first pass-
StudentID|TestDuration
0|StudentID|TestDuration
-second pass-
StudentID|AssessmentScores
1|StudentID|AssessmentScores
This is what I expect to output... However at the end of the code snippet when it runs the for loops to spit out all the values I get the following alerts...
0|StudentID|AssessmentScores
1|StudentID|AssessmentScores
I can't for the life of me figure out why it's replacing the first value with the second value. I thought it might be using a reference variable which is why I added in the P and V variables to try to get around that if that was the case, but the results are the same.

This is because you are adding the same variable every iteration of the loop.
Try changing your push like this:
SubAssessmentScores.push({
Parent: P,
Value: V
});
That said, I recommend you study a little more javascript and conventions in the language, for example your variable naming is frowned upon because you should only use capital letters on the beginning of a name for constructor functions.
A good book is Javascript the good parts by Douglas Crockford.

Not able to compare variables in JQuery

I have an array of records. I want to search a string at the specific position of the array. But some how I am not able to do so. Kindly see the code below:
var match_index = [];
var count = 0;
var keyword1 = csvvalue[1][9].replace(/\"/g, '');
var search_text="इलाहाबाद";
$("#leng").html(csvvalue.length);
for(var i=0; i<csvvalue.length; i++){
$("#index").html("loop");
var keyword1 = csvvalue[i][9].replace(/\"/g, '');
if (search_text === keyword1)
{
match_index[count] = i;
count++;
$("#index").html("match");
}
$("#index").append("<br />" + i.toString());
}
In the above code, the control is is not going inside the if statement, though the string is available in the array at index 1 and 2. Also only the last value of i is getting printed (last line of the code) though it should print all the values of i starting from 0.
My actual requirement is to search through entire array for a specific string. I have changed the code to suit my requirement better.
Edited
I tried every thing but the control is not going inside the if statement though there are two matching records

You are comparing two values set before the loop
I guess it should be more like :
var match_index = [];
var count = 0;
var keyword1 = "";
var search_text="इलाहाबाद";
$("#leng").html(csvvalue.length);
for(var i=0; i<csvvalue.length; i++){
keyword1 = csvvalue[i].replace(/\"/g, '');
$("#index").html("loop");
if (search_text === keyword1)
{
match_index[count] = i;
count++;
$("#index").html("match");
}
$("#index").append("<br />" + i.toString());
}
Or depending on how your csvvalue array is structured.
keyword1 = csvvalue[1][i].replace(/\"/g, '');

Why loop through the whole array if you want to check a specific variable in the array.
You could just do something like
if (search_text === csvvalue[1][9].replace(/\"/g, '') {
//do something
}
Unless you really need to know how many times you run through the array.

fastest way to loop through an array

I want to return an array when one of the elements matches an item within an array.
Is the below code the fastest way to loop through an array when a value matches in a javascript array of arrays?
Note : Welcome any suggestions to modify the variable relatedVideosArray to make it a different data structure for better performance.
var relatedVideosArray = [
["1047694110001"],
["1047694111001", "1019385098001","1020367665001","1020367662001", "1019385097001", "1020367667001"],
["1040885813001"],
["1019385094001", "1019385096001"],
["952541791001", "952544511001", "952544512001", "952544508001", "952541790001","952580933001", "952580934001", "1051906367001"]
]
function getRelatedVideos(videoClicked){
var tempStoreArray = [];
var getCurrentId = videoClicked;
var relVideoslen = relatedVideosArray.length;
for(var i in relatedVideosArray) {
tempStoreArray = relatedVideosArray[i];
for(var j in tempStoreArray){
if(tempStoreArray[j] == getCurrentId){
return relatedVideosArray[i];
}
}
}
}
Update: I initially thought of making a key of video ids and values as all the related ids, but I want to display the key as well as all the related ids if any of the ids within the value array are clicked. Hope this helps to explain the constraint I have.

Modern day browsers support Array indexOf.
For the people saying the array indexOf is slower, basic tests on speed.
var values = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];
console.time("for");
for(var i=0;i<1000;i++){
for(var j=0;j<=values.length;j++){
if(values[j]===20) break;
}
}
console.timeEnd("for");
console.time("reverse for");
for(i=0;i<1000;i++){
for(var j=values.length-1;j>=0;j--){
if(values[j]===1) break;
}
}
console.timeEnd("reverse for");
console.time("while");
for(i=0;i<1000;i++){
var j=0;
while (j<values.length){
if(values[j]===20) break;
j++;
}
}
console.timeEnd("while");
console.time("reverse while");
for(i=0;i<1000;i++){
var j=values.length-1;
while (j>=0){
if(values[j]===1) break;
j--;
}
}
console.timeEnd("reverse while");
console.time("indexOf");
for(var i=0;i<1000;i++){
var x = values.indexOf(20);
}
console.timeEnd("indexOf");
console.time("toString reg exp");
for(var i=0;i<1000;i++){
var x = (/(,|^)20(,|$)/).test(values.toString);
}
console.timeEnd("toString reg exp");
Two possible solutions:
var relatedVideosArray = [
["1047694110001"],
["1047694111001", "1019385098001","1020367665001","1020367662001", "1019385097001", "1020367667001"],
["1040885813001"],
["1019385094001", "1019385096001"],
["952541791001", "952544511001", "952544512001", "952544508001", "952541790001","952580933001", "952580934001", "1051906367001"]
]
//var getCurrentId = "1019385098001";
var getCurrentId = "1040885813001";
console.time("indexOf");
var tempStoreArray = [];
for(var i = relatedVideosArray.length-1; i>=0; i--){
var subArr = relatedVideosArray[i];
if(subArr.indexOf(getCurrentId)!==-1){
tempStoreArray.push(subArr);
}
}
console.timeEnd("indexOf");
console.log(tempStoreArray);
console.time("toString reg exp");
var tempStoreArray = [];
var re = new RegExp("(,|^)" + getCurrentId + "(,|$)");
for(var i = relatedVideosArray.length-1; i>=0; i--){
var subArr = relatedVideosArray[i];
if(re.test(subArr.toString())){
tempStoreArray.push(subArr);
}
}
console.timeEnd("toString reg exp");
console.log(tempStoreArray);

I believe so if you keep your current structure. Unless you have a way of 'flattening' the array first, so that rather than being nested, there is simply one array with all the values. If this is out of your control or impractical, then you have no other choice than to iterate over every element and its elements.
Otherwise, would you be able to add the values to a map? The current video id would be the key, and the value would be the list of related videos.

If you have control over the data structure then I highly recommend changing it to something more amenable to the type of searches you are performing. First thing that comes to mind is an array of associative arrays. Each of your video arrays would be keyed with the video id ( set the value to anything you want ). That would make your search O(n), where n = the total number of video lists you have.
I'll post some code for this when I get in front of the computer.

Remove element from list - JQuery/JavaScript

I have a list like this in a div:
<div id="x">5,2,3,1,4,9,8</div>
How do I simply remove a given element from this list?
JQuery or JavaScript may be used.
Please note that the numbers in the list are unique and they are coming in from a database of type int(11), they are not in any sort of order.
Any help appreciated guys...

First, get the text:
var text=$("#x").text();
Then split it:
var items=text.split(',');
If there's no items, you'll have an empty string as the only element of the array. If so, empty the array:
if(items.length==1&&items[0]=="") {
items=[];
}
Now convert everything to an integer: (note that this step isn't actually required, but if you're doing anything else with items, it's nice to have)
items=items.map(function(str) { return parseInt(str, 10); });
Put the item you want to remove in a variable:
var itemToRemove=3;
Find that in the array:
var index=items.indexOf(itemToRemove);
If it was found, splice it out of the array:
if(index!==-1) {
items.splice(index, 1);
}
Join the items back together:
text=items.join(',');
Put it back in the element:
$("#x").text(text);

Try this with toRemove equal to 5, 3, or 8 to see that it works for all cases:
var toRemove = 3; // the number you want to remove
$('#x').text($('#x').text().replace(new RegExp(toRemove + ',?'
+ '|,?' + toRemove + '$'), ''));
See example →

Using jQuery's grep-method may be an option too:
var toRemove=1;
$('#x').text( $.grep($('#x').text().split(','),
function (a) { return a != toRemove; }).join(','));
To remove multiple items:
var toRemove=[1,8,3];
$('#x').text( $.grep($('#x').text().split(','),
function (a) { return $.inArray(Number(a),toRemove)<0; })
.join(','));
(But I would prefer a RegExp-solution, it should be much faster)

This is a simple solution that just requires jquery.
function removeFromDiv(which)
{
var data = $("#x").html();
data_arr = data.split(",");
for (var i = 0; i < data_arr.length; i++)
{
if (data_arr[i] == which)
{
data_arr.splice(i, 1);
data = data_arr.join(",");
}
}
$("#x").html(data);
}
then simply run:
removeFromDiv("4");

Doesn't really need to be much harder than this:
function removeIndexFromX(index) {
// Build array from comma-delimited content
var arr = $("#x").text().split(',');
// Remove index (zero-based)
arr.splice(index, 1);
// Replace
$("#x").text(arr.join(','));
}
function removeNumberFromX(num) {
var arr = $("#x").text().split(',');
for (var i = 0; i < arr.length; i++) {
if (arr[i] === num) {
arr.splice(i, 1);
}
}
$("#x").text(arr.join(','));
}
The benefit of split and join is that you can use those to manage delimiters (e.g. commas) for you.