I`m trying to sum the values of the elements in an array using javascript, this is my script.
function sumAll()
{
var totalOverheads = 0;
var overheads = new Array();
overheads = document.getElementsByName('overhead');
for(i=0;i<overheads.length;i++)
if(!isNaN(overheads[i].value) || overheads[i].value != null || overheads[i].value != "" || overheads[i].value != '' || overheads[i].value != NULL)
alert(overheads[i].value);
//totalOverheads = parseInt(totalOverheads) + parseInt(overheads[i].value);
alert(totalOverheads);
}
for now, in the if condition inside the for loop, I`m displaying the value of the item in an alert, yet it`s not working correctly, it just displays all the items even if the item is not a number, how can I perform an operation if the input is only a number?
getElementsByName returns a NodeList. Not sure if that was the problem, but anyway:
var totalOverheads = 0;
var overheads = document.getElementsByName('overhead');
var n;
var i; // <<--- don't forget to initialise i
for (i = 0; i < overheads.length; ++i) {
n = parseInt(overheads.item(i).value, 10);
if (!isNaN(n)) {
totalOverheads += n;
}
}
alert(totalOverheads);
Also, please use brackets!
Related
The goal of this "counter" is to see how many different words are inside the "ToCount"string. To do that it makes ToCount an array and then iterates over the elements, checking if they already are there and if not, adding them there.
The ToCountArr2 remains empty after the loop and a length of 0 is being displayed. Why does that happen and what can I do about it?
I ran a debugger and saw that no elements are added to the second list, as if nothing appenned inside the "if" control if the i-th element of the first array already is inside the second array.
function counter(){
var ToCount = document.getElementById("demo").value; //the contents of a textbox
var ToCountArr1 = ToCount.split(" ");
var ToCountArr2 = new Array;
var i = 0;
var lengthToCountArr1 = ToCountArr1.length;
var wordToPush;
while (i < lengthToCountArr1){
if(ToCountArr2.includes(ToCountArr1[i] === false)) {
wordToPush = ToCountArr1[i];
ToCountArr2.push(wordToPush);
}
i = i + 1;
}
alert(ToCountArr2.length);
}
The issue is with this line if(ToCountArr2.includes(ToCountArr1[i] === false)). Here the braces need to be after ToCountArr1[i], where as this line ToCountArr1[i] === false) is checking whether that value in ToCountArr1 is true or false.
This line
if(ToCountArr2.includes(ToCountArr1[i] === false)) will be evaluated as
if(ToCountArr2.includes(true/false))
depending on result of ToCountArr1[i] === false)
function counter() {
var ToCount = document.getElementById("demo").value; //the contents of a textbox
var ToCountArr1 = ToCount.split(" ");
var ToCountArr2 = new Array;
var i = 0;
var lengthToCountArr1 = ToCountArr1.length;
var wordToPush;
while (i < lengthToCountArr1) {
if (ToCountArr2.includes(ToCountArr1[i]) === false) {
wordToPush = ToCountArr1[i];
ToCountArr2.push(wordToPush);
}
i = i + 1;
}
console.log(ToCountArr2.length);
}
counter()
<input type='text' id='demo' value='Test Values'>
You can minimize if (ToCountArr2.includes(ToCountArr1[i]) === false) { by replacing it with
if (!ToCountArr2.includes(ToCountArr1[i])) {
Your wordcount function should use a parameter so you can pass a string in. This means you can use the wordcount function on an any string, not just the "demo" element. Also, this is a good time to learn about Map -
const wordcount = (str = "") =>
{ const result =
new Map
for (const s of str.split(/ /))
if (s === "")
continue
else if (result.has(s))
result.set(s, result.get(s) + 1)
else
result.set(s, 1)
return Array.from(result.entries())
}
const prettyPrint = (value) =>
console.log(JSON.stringify(value))
<!-- pass this.value as the string for wordcount
-- wordcount returns a value that we could use elsewhere
-- prettyPrint displays the value to the console
-->
<input onkeyup="prettyPrint(wordcount(this.value))">
Run the code snippet and copy/paste the following line into the field -
this is the captain speaking. is this the commander?
You will see this output -
[["this",2],["is",2],["the",2],["captain",1],["speaking.",1],["commander?",1]]
Here is an working example. I think it will help you right way. Here I use indexOf to check the value exist on a array.
function counter(){
var ToCount = "I am string just for text.";//document.getElementById("demo").value; //the contents of a textbox
var ToCountArr1 = ToCount.split(" ");
var ToCountArr2 = new Array;
var i = 0;
var lengthToCountArr1 = ToCountArr1.length;
var wordToPush;
while (i < lengthToCountArr1){
if( ToCountArr2.indexOf(ToCountArr1[i]) == -1 ) {
wordToPush = ToCountArr1[i];
ToCountArr2.push(wordToPush);
}
i = i + 1;
}
alert(ToCountArr2.length);
}
counter();
I am receiving a type error stating that the array testA[i] is undefined whenever I add an input into the html page. I have the array set and i'm trying to add the value of currency to the array using the push method to add to the second part of the array i.e([0][currency])
function Test() {
var testA = [];
for (i = 0; i < 4; i++) {
this.currency = prompt("Please enter a 3-letter currency abbreviation", "");
testA[i].push(currency);
}
}
var index = new Test();
any help as to why the array is undefined would be appreciated.
Note: I have now tried both testA.push(currency) and testA[i] = this.currency, and I still get the same error as before.
Note: the final version should have it loop through 4 different questions asked and each time adding these into an array. At the end of the loop a new variant of the array should be made and the new set of data entered will be added to it. something like
for(i = 0; i < 4; i++) {
testA[i] = i;
for(j = 0; j < 4; j++) {
this.currency = prompt("Please enter a 3-letter currency abbreviation", "");
testA[i][j] = this.currency;
}
}
but at this point in time I'm just trying to get it to work.
You don't use the push method on a index. You use it on the array itself.
Replace this
testA[i].push(currency);
With this
testA.push(currency);
You need to perform push operation on the array directly.
testA.push(currency);
By executing testA[index] you will receive hold value. In JS it will always return undefined, if index is greater than array length.
Because your array is empty as the beginning, you are always receiving undefined.
You are mixing up two different implementation.
Either you use direct assignation.
var testA = new Array(4);
for (i = 0; i < 4; i += 1) {
this.currency = prompt('...', '');
testA[i] = this.currency;
}
Either you push new values into the array.
var testA = [];
for (i = 0; i < 4; i += 1) {
this.currency = prompt('...', '');
testA.push(this.currency);
}
You should use the second one, which is the most simple soluce.
testA[i] = this.currency OR testA.push(this.currency)
Use Modified function below
function Test() {
var testA = [];
for (i = 0; i < 4; i++) {
this.currency = prompt("Please enter a 3-letter currency abbreviation", "");
testA[i] = this.currency; // use this.currency here if you
}
console.log(testA);
}
var index = new Test();
I had ten rows which each rows contain 4 column, now I want to get the value which I had import using localStorage. I find a way to put all these value independently but the code is all the repeat one. These will cause to redundancy of code. I wonder if there are a way to shorten the code using loop?
Here is my code
var res = {};
$(function(){
$('#subbtn').click(function() {
console.log($('#tab').find('tr'))
$('tr').each(function(){
var tmp = [];
var cl ;
$(this).find('select').each(function(){
cl = $(this).attr('class');
//console.log(cl);
tmp.push($(this).val());
})
res[cl] = tmp
})
console.log(res);
localStorage.setItem("testingvalue",JSON.stringify(res));
document.getElementById("results__display").innerHTML = (localStorage.getItem("testingvalue"));
})
})
$( document ).ready(function(){
var res = {};
try {
console.log('existed');
res = JSON.parse(localStorage.getItem("testingvalue"));
//alert(res.r1[2]);
document.getElementsByClassName("r1")[0].selectedIndex=res.r1[0];
document.getElementsByClassName("r1")[1].selectedIndex=res.r1[1];
document.getElementsByClassName("r1")[2].selectedIndex=res.r1[2];
document.getElementsByClassName("r1")[3].selectedIndex=res.r1[3];
document.getElementsByClassName("r2")[0].selectedIndex=res.r2[0];
document.getElementsByClassName("r2")[1].selectedIndex=res.r2[1];
document.getElementsByClassName("r2")[2].selectedIndex=res.r2[2];
document.getElementsByClassName("r2")[3].selectedIndex=res.r2[3];
document.getElementsByClassName("r3")[0].selectedIndex=res.r3[0];
document.getElementsByClassName("r3")[1].selectedIndex=res.r3[1];
document.getElementsByClassName("r3")[2].selectedIndex=res.r3[2];
document.getElementsByClassName("r3")[3].selectedIndex=res.r3[3];
document.getElementsByClassName("r4")[0].selectedIndex=res.r4[0];
document.getElementsByClassName("r4")[1].selectedIndex=res.r4[1];
document.getElementsByClassName("r4")[2].selectedIndex=res.r4[2];
document.getElementsByClassName("r4")[3].selectedIndex=res.r4[3];
document.getElementsByClassName("r5")[0].selectedIndex=res.r5[0];
document.getElementsByClassName("r5")[1].selectedIndex=res.r5[1];
document.getElementsByClassName("r5")[2].selectedIndex=res.r5[2];
document.getElementsByClassName("r5")[3].selectedIndex=res.r5[3];
document.getElementsByClassName("r6")[0].selectedIndex=res.r6[0];
document.getElementsByClassName("r6")[1].selectedIndex=res.r6[1];
document.getElementsByClassName("r6")[2].selectedIndex=res.r6[2];
document.getElementsByClassName("r6")[3].selectedIndex=res.r6[3];
document.getElementsByClassName("r7")[0].selectedIndex=res.r7[0];
document.getElementsByClassName("r7")[1].selectedIndex=res.r7[1];
document.getElementsByClassName("r7")[2].selectedIndex=res.r7[2];
document.getElementsByClassName("r7")[3].selectedIndex=res.r7[3];
document.getElementsByClassName("r8")[0].selectedIndex=res.r8[0];
document.getElementsByClassName("r8")[1].selectedIndex=res.r8[1];
document.getElementsByClassName("r8")[2].selectedIndex=res.r8[2];
document.getElementsByClassName("r8")[3].selectedIndex=res.r8[3];
document.getElementsByClassName("r9")[0].selectedIndex=res.r9[0];
document.getElementsByClassName("r9")[1].selectedIndex=res.r9[1];
document.getElementsByClassName("r9")[2].selectedIndex=res.r9[2];
document.getElementsByClassName("r9")[3].selectedIndex=res.r9[3];
document.getElementsByClassName("r10")[0].selectedIndex=res.r10[0];
document.getElementsByClassName("r10")[1].selectedIndex=res.r10[1];
document.getElementsByClassName("r10")[2].selectedIndex=res.r10[2];
document.getElementsByClassName("r10")[3].selectedIndex=res.r10[3];
}
catch (error){
console.log(error.message);
}
});
Looking at this repeated line:
document.getElementsByClassName("r1")[0].selectedIndex=res.r1[0];
...a simple first pass improvement would be to just use a nested for loop with variables instead of "r1" and 0:
for (var r = 1; r <= 10; r++) {
for (var i = 0; i < 4; i++) {
document.getElementsByClassName("r" + r)[i].selectedIndex = res["r" + r][i];
}
}
Notice, though, that this means the .getElementsByClassName("r" + r) call happens four time for each value of r, which is not very efficient - it would be better to move that into the outer loop:
var els;
for (var r = 1; r <= 10; r++) {
els = document.getElementsByClassName("r" + r);
for (var i = 0; i < 4; i++) {
els[i].selectedIndex = res["r" + r][i];
}
}
In the second version the inner loop could say i < els.length rather than i < 4, although note that either way you need to be sure you match the number of HTML elements to the number of items in your res object.
You've seem to have the jQuery library loaded. Using jQuery makes this much easier.
Here is an example:
var res = JSON.parse(localStorage.getItem("testingvalue"));
$("tr select").each(function(){
$(this).val(res[$(this).attr("class")][$(this).index()]);
});
Of course, this will only work if the select elements have only one class name and the res object contains values for all the select elements that are inside tr elements. Based on the jQuery code in your question that seems to be the case.
And this is a safer approach
Object.keys(res).forEach(function(key){
res[key].forEach(function(val, index){
$("tr select." + key).eq(index).val(val);
});
});
Code below will work regardless the size of your data in storage:
res = JSON.parse(localStorage.getItem("testingvalue"));
// Let's start with checking 'res' type.
// - if it's an Array, get the the length from .length
// - if it's Object, get the the length from Object.keys().length
var resLength = Array.isArray(res) ? res.length : typeof res === 'object' ? Object.keys(res).length : 0;
// loop throw the rows.
for (var i = 0; i < resLength; i++) {
// Do the same as above: get type of the row and calculate it length for the loop.
var rowLength = Array.isArray(res[i]) ? res.length : typeof res[i] === 'object' ? Object.keys(res[i]).length : 0;
// loop throw the columns on the row.
for (var j = 0; j < rowLength; j++) {
document.getElementsByClassName('r'+i)[j].selectedIndex=res['r'+i][j];
}
}
have to search for classname with string matching "Routed:" then get the string of the following classname in this case "W000000" in the image below. there are over 65 of these on the page at any given time i just need to get the first one and store that value.
You could use a for loop for the elements and get the next one.
var tds = document.getElementsByClassName('ms-cellstyle ms-vb2');
var found = false;
var firstValue = '';
for (var i = 0; i < tds.length && !found; i++) {
if (tds[i].innerHTML.indexOf('Routed') >= 0 && i < tds.length - 1) {
firstValue = tds[i + 1].innerHTML;
found = true;
}
}
console.log(firstValue);
I am trying to grab a certain value. I am new to javascript and I can't figure out why this is not working.
If I parse "kid_2" I should get "kostas". Instead of "Kostas" I always get "02-23-2000". So I must have a logic problem in the loop but I am really stuck.
function getold_val(fieldname,str){
var chunks=str.split("||");
var allchunks = chunks.length-1;
for(k=0;k<allchunks;k++){
var n=str.indexOf(fieldname);
alert(chunks[k]);
if(n>0){
var chunkd=chunks[k].split("::");
alert(chunkd);
return chunkd[1];
}
}
}
var test = getold_val('kid_2','date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||');
alert(test);
A regex may be a little more appealing. Here's a fiddle:
function getValue(source, key){
return (new RegExp("(^|\\|)" + key + "::([^$\\|]+)", "i").exec(source) || {})[2];
}
getValue("date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||","kid_2");
But if you want something a little more involved, you can parse that string into a dictionary like so (fiddle):
function splitToDictionary(val, fieldDelimiter, valueDelimiter){
var dict = {},
fields = val.split(fieldDelimiter),
kvp;
for (var i = 0; i < fields.length; i++) {
if (fields[i] !== "") {
kvp = fields[i].split(valueDelimiter);
dict[kvp[0]] = kvp[1];
}
}
return dict;
}
var dict = splitToDictionary("date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||","||","::");
console.log(dict["date_1"]);
console.log(dict["date_2"]);
console.log(dict["kid_1"]);
console.log(dict["kid_2"]);
This works, here's my fiddle.
function getold_val(fieldname,str) {
var chunks = str.split('||');
for(var i = 0; i < chunks.length-1; i++) {
if(chunks[i].indexOf(fieldname) >= 0) {
return(chunks[i].substring(fieldname.length+2));
}
}
}
alert(getold_val('kid_2', 'date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||'));
The issue with your code was (as #slebetman noticed as well) the fact that a string index can be 0 because it starts exactly in the first letter.
The code is almost the same as yours, I just didn't use the second .split('::') because I felt a .substring(...) would be easier.
There are two bugs. The first error is in the indexOf call:
var n = str.indexOf(fieldname);
This will always return a value greater than or equal to 0 since the field exists in the string. What you should be doing is:
var n = chunks[k].indexOf(fieldname);
The second error is in your if statement. It should be:
if(n >= 0) {
...
}
or
if(n > -1) {
...
}
The substring you are looking for could very well be the at the beginning of the string, in which case its index is 0. indexOf returns -1 if it cannot find what you're looking for.
That being said, here's a better way to do what you're trying to do:
function getold_val(fieldName, str) {
var keyValuePairs = str.split("||");
var returnValue = null;
if(/||$/.match(str)) {
keyValuePairs = keyValuePairs.slice(0, keyValuePairs.length - 1);
}
var found = false;
var i = 0;
while(i < keyValuePairs.length && !found) {
var keyValuePair = keyValuePairs[i].split("::");
var key = keyValuePair[0];
var value = keyValuePair[1];
if(fieldName === key) {
returnValue = value;
found = true;
}
i++;
}
return returnValue;
}