Writing to an array by index

It seems to work! There are many dip days. But so far nothing is clear.

In order to clarify the picture, I propose to collect data about the dips in the new array and log it on the second graph. To do this, you will have to write data to an array. Writing to an array is done in the same way as reading: by accessing an element using square brackets:

var numbers = [];
var index = 1;

numbers[0] = 1;
numbers[index] = 2;

// Will log [1,2]
console.log(numbers);

Note that if there is no element in the array under the number under which we write it, then this element will be created. Before executing the code in the array, there was neither zero nor the first element, but after we wrote down the values ​​in these positions, the elements were added to the array.

In order to maintain consistency with the first graph, we will form an array with dip days in the same loop, where we summarize traffic. If traffic on the i-th day is good, we will write zero dips in the i-th element of the array, if traffic is bad, we will write the dip value there.

To calculate dip value, we will subtract the actual traffic value from the expected value. For example:

1. Traffic on the fifth day was 681 people.
2. Difference between expected and actual traffic: 1000 - 681 = 319.
3. It means 319 people is the traffic dip value on the fifth day.