I'm following a coursera course and I'm a bit stuck on a line of code. I understand what it does but not why. The video explains how to get the avarage value of an Array.
I found this code online and its exactly the part that I don't get:
var numbers = [10, 20, 30, 40] // sums to 100
var sum = 0;
for (var i = 0; i < numbers.length; i++) {
sum += numbers[i]
}
I don't get this part:
sum+=numbers[i]
I read it as sum = 0+4.
What am I missing?
Basically what is says is "take whatever is in the i position of the numbers and add it to the value of sum".
So for example, if i = 2, then "whatever is in the i position of numbers would be 30.
To elaborate further, var numbers = [10, 20, 30, 40] can also be written as:
var numbers = [];
numbers[0] = 10;
numbers[1] = 20;
numbers[2] = 30;
numbers[3] = 40;
Hope this helps you understand better.
In sum += numbers[i], with operator += means sum = sum + numbers[i]
numbersis a list with values at indices. you reference the values with an index/indices using[], in this case i (which is 0, 1, 2, 3 -numbers.lengthis how many elements are in numbers)4come from? Do you know what+=does? Also see How does += (plus equal) work?. Or is itnumbers[i]you’re having trouble with? See MDN.