Calcurate your mortgage vol2.

the update source code from the version of this.

> mortgage
function(P=5000000, I=0.775, L=300, amort=T, plotData=T) {
J <- I/(12 * 100)
N <- L
M <- P*J/(1-(1+J)^(-N))
monthPay <<- M
cat("\nThe payments for this loan are:\n\n\n",
"\tMonthly payment: \t￥",format(M, big.mark=",", scientific=F)," (stored in monthPay)\n",
"\tTotal cost: \t\t￥", format(M*N, big.mark=",", scientific=F), "\n\n", sep="")
# Calculate Amortization for each Month
if(amort==T) {
Pt <- P # current principal or amount of the loan
currP <- NULL
while(Pt>=0) {
H <- Pt * J # this is the current monthly interest
C <- M - H # this is your monthly payment minus your monthly interest, so it is the amount of principal you pay for that month
Q <- Pt - C # this is the new balance of your principal of your loan
Pt <- Q # sets P equal to Q and goes back to step 1. The loop continues until the value Q (and hence P) goes to zero
currP <- c(currP, Pt)
}
monthP <- c(P, currP[1:(length(currP)-1)])-currP
aDFmonth <<- data.frame(
      Amortization=c(P, currP[1:(length(currP)-1)]),
      Monthly_Payment=monthP+c((monthPay-monthP)[1:(length(monthP)-1)],0),
      Monthly_Principal=monthP,
      Monthly_Interest=c((monthPay-monthP)[1:(length(monthP)-1)],0),
      Year=sort(rep(1:ceiling(N/12), 12))[1:length(monthP)]
)
aDFyear <- data.frame(
     Amortization=tapply(aDFmonth$Amortization, aDFmonth$Year, max),
     Annual_Payment=tapply(aDFmonth$Monthly_Payment, aDFmonth$Year, sum),
     Annual_Principal=tapply(aDFmonth$Monthly_Principal, aDFmonth$Year, sum),
     Annual_Interest=tapply(aDFmonth$Monthly_Interest, aDFmonth$Year, sum),
     Year=as.vector(na.omit(unique(aDFmonth$Year)))
     )
aDFyear <<- aDFyear
cat("The amortization data for each of the", N, "months are stored in \"aDFmonth\".\n\n")
cat("The amortization data for each of the", L/12, "years are stored in \"aDFyear\".\n\n")
# may edit "L/12" in the previous line.
}
if(plotData==T) {
barplot(t(aDFyear[,c(3,4)]),
col=c("blue", "red"),
main="Annual Interest and Principal Payments",
sub="The data for this plot is stored in aDFyear.",
xlab="Years", ylab=" Amount",
legend.text=c("Principal", "Interest"),
ylim=c(0, max(aDFyear$Annual_Payment)*1.3))
}
}