how to calculate the sum of the sales figures the previous 5 days with rstudio so the forecast?

Question

I have a table in Rstudio and my table had 4 attributes and I want to know how to calculate the forecast for example the sum of the sales in the previous 5 days

Answer 1

Something tells me that this is from a school-assignement, so I won't give you the entire answer.

Say your table looks somewhat like this

id	date	sales
1	2021-12-30	100
2	2021-12-31	110
3	2022-01-01	120
4	2022-02-01	130
5	2022-03-01	140
6	2022-04-01	150
7	2022-05-01	160

The algorithm for computing the sum of the last five days, say between 2021-12-31 and 2022-01-04, would be something a long the lines of

1. Filter away all rows that have date < 2021-12-31
2. Filter away all rows that have date > 2021-01-04
3. Use a sum-function on the sales-column on the remaining table.

If you can use dplyr , you could probably do everything in two lines of code.