I am trying to get the script to calculate the average from numbers entered into a text area. The numbers are seperated by a comma
I either get a NaN value or it just doesnt work right.
This code came closest to actually working. However it only adds the comma as a new element and all numbers are just combined in the first element, dividing the number by the amount of comma's.
document.querySelector("#input").addEventListener("input", function test() {
const strng = document.getElementById("input").value;
var arr = strng.split(',');
const avg = arr.reduce((a, b) => a + b, 0) / arr.length;
document.getElementById("lbl").innerHTML = avg;
});
function cycle() {
var area = document.getElementById("txt").value;
var lines = area.split(',');
const average = arr => arr.reduce((a, b) => a + b, 0) / arr.length;
document.getElementById("lbl").innerHTML = average([lines]).toFixed(2);
}
setInterval(cycle, 100)<textarea id="input"></textarea>
<label id="lbl">Result Here</label>
<textarea id="txt"></textarea>The cycle() function gave me a NaN value right after entering the first comma in the textarea.
Can someone help me out?
When you split a string from user input you get an array of strings. Thus you have to parse these strings into numbers and filter out any non numeric values before calculation.
function test() {
const inputValue = document.getElementById("input").value;
var values = inputValue.split(',').map(v => parseFloat(v)).filter(v => !Number.isNaN(v));
const avg = values.reduce((a, b) => a + b, 0) / values.length;
document.getElementById("lbl").innerHTML = (!Number.isNaN(avg)) ? avg : '';
}
setInterval(test, 100);<textarea id="input"></textarea><br>
<label id="lbl">Result Here</label>
<textarea id="txt"></textarea>// access the DOM elements
const inpTxt = document.getElementById("input");
const outTxt = document.getElementById("lbl");
// add event listener to text-area "input" event
inpTxt.addEventListener("input", () => {
// collect the list of comma separated numbers into an array "numList"
const numList = inpTxt
.value // access the DOM element "inpTxt"'s value attribute
.split(',') // ".split()" using "comma" as the seperator
.map(Number) // convert each element into a number
.filter( // sanity check to remove any non-number data
x => !isNaN(x)
);
console.log(numList); // to see in real-time the "numList" array on console
if (numList.length) { // if there are any valid numbers in the array
outTxt.innerText = ( // change the "label"'s innerText
numList.reduce( // sum the numbers in the "numList" array
(total, num) => total + num,
0 // initialize the "sum" to zero
) / // divide into "numList.length" to compute average
numList.length
);
}
});<div>
Type comma-separated numbers in below input box
and average will be calculated
</div>
<div><textarea id="input"></textarea></div>
<div><label id="lbl">Result Here</label></div>