# R - Excel Helpers
*Source: https://kotamine.github.io/excel_shiny/tips-from-excel-tool-to-shiny.html*
Some [[2-Areas/MOCs/R]] functions related to familiar [[Excel]] functions:
## Net Present Value - NPV
```R
#' Net Present Value
#'
#' @param rate Rate to use when discounting
#' @param values Vector of numeric values to discount to present value
npv <- function(rate, values) {
sum(values / (1 + rate) ^ seq_along(values))
}
```
## Internal Rate of Return
```R
***
## Appendix: Links
- [[Code]]
- [[R]]
- [[Development]]
*Backlinks:*
```dataview
list from [[R - Excel Helpers]] AND -"Changelog"
```