Skip to content Maëlle Salmon 96cc7b0 Jul 2, 2018
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 #' Calculates the compound interest rate for a loan #' #' Based on period interest rate, number of periods, and loan amount, this function calculates #' the compound annual interest rate of the loan based on the monthly repayment. #' It calculates based on a fixed interest rate, FV=0, and charging is #' at the end of the period. #' #' @param nper Number of periods - monthly #' @param pmt Instalment per period (should be negative) #' @param pv Present value i.e. loan advance (should be positive) #' @param fv Future value i.e. redemption amount #' #' @return rate The effective interest rate per year #' #' @keywords financial pv pmt apr #' @seealso \code{\link{RATE}} #' @family finance #' @export #' #' @examples #' # single set of values #' APR(12,-10,110) #' #' # vector of values #' df<-data.frame(nper=c(12,24),pmt=c(-10,-10),pv=c(110,220)) #' APR(df\$nper,df\$pmt,df\$pv) #' APR <- function(nper, pmt, pv, fv = 0) { stopifnot(nper >= 1, pmt < 0, pv > 0) rate <- ((1 + RATE(nper, pmt, pv, fv))^12) - 1 return(rate) }
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