Automatic vlookup and multiply coefficients with R - r

Question

I´m trying to code a function in R (stats programming language) that would allow me to automate the calculation of a linear regression (lm)
The problem:
The regression is calculated through the "step" function, so the coefficients selected cannot be known in advance.
Problem
Automate identifying the coefficients selected by the step function.
Vlookup and cross multiply the second column of the results Ex."View(OpenCoefs)" (estimates) with the last row(last day) of respective columns of the original data frame "sp"
The desirable solution would be a function that i would just type "run()" that would return the "y"s for each regression, namely, the forecast of the S&P500 index for the following day(Open, Low, High,Close).
The code retrieves data from the yahoo finance website, so it´s operational if you run it.
Here´s the code.
sp <- read.csv(paste("http://ichart.finance.yahoo.com/table.csv?s=%5EGSPC&a=03&b=1&c=1940&d=03&e=1&f=2014&g=d&ignore=.csv"))
sp$Adj.Close<-NULL
sp<-sp[nrow(sp):1,]
sp<-as.data.frame(sp)
for ( i in 2:nrow( sp ) ) {
sp[ i , "Gr_Open" ] <-
( sp[ i , "Open" ] / sp[ i - 1 , "Open" ] ) - 1
}
for ( i in 2:nrow( sp ) ) {
sp[ i , "Gr_High" ] <-
( sp[ i , "High" ] / sp[ i - 1 , "High" ] ) - 1
}
for ( i in 2:nrow( sp ) ) {
sp[ i , "Gr_Low" ] <-
( sp[ i , "Low" ] / sp[ i - 1 , "Low" ] ) - 1
}
for ( i in 2:nrow( sp ) ) {
sp[ i , "Gr_Close" ] <-
( sp[ i , "Close" ] / sp[ i - 1 , "Close" ] ) - 1
}
for ( i in 2:nrow( sp ) ) {
sp[ i , "Gr_Volume" ] <-
( sp[ i , "Volume" ] / sp[ i - 1 , "Volume" ] ) - 1
}
nRows_in_sp<-1:nrow(sp)
sp<-cbind(sp,nRows_in_sp)
Open_Rollin<-NA
sp<-cbind(sp,Open_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "Open_Rollin" ]<-0
} else {
sp[ i , "Open_Rollin" ]<-(( mean(sp[,"Open"][(i-100):i])))
}
}
Close_Rollin<-NA
nRows_in_sp<-1:nrow(sp)
sp<-cbind(sp,Close_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , " Close_Rollin" ]<-0
} else {
sp[ i , "Close_Rollin" ]<-(( mean(sp[,"Close"][(i-100):i])))
}
}
Low_Rollin<-NA
sp<-cbind(sp,Low_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "Low_Rollin" ]<-0
} else {
sp[ i , "Low_Rollin" ]<-(( mean(sp[,"Low"][(i-100):i])))
}
}
High_Rollin<-NA
sp<-cbind(sp,High_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "High_Rollin" ]<-0
} else {
sp[ i , "High_Rollin" ]<-(( mean(sp[,"High"][(i-100):i])))
}
}
Open_GR_Rollin<-NA
sp<-cbind(sp,Open_GR_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "Open_GR_Rollin" ]<-0
} else {
sp[ i , "Open_GR_Rollin" ]<-(( mean(sp[,"Gr_Open"][(i-100):i])))
}
}
Close_GR_Rollin<-NA
sp<-cbind(sp, Close_GR_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "Close_GR_Rollin" ]<-0
} else {
sp[ i , "Close_GR_Rollin" ]<-(( mean(sp[,"Gr_Close"][(i-100):i])))
}
}
Low_GR_Rollin<-NA
sp<-cbind(sp, Low_GR_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "Low_GR_Rollin" ]<-0
} else {
sp[ i , "Low_GR_Rollin" ]<-(( mean(sp[,"Gr_Low"][(i-100):i])))
}
}
High_GR_Rollin<-NA
sp<-cbind(sp, High_GR_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]<=1000)
{
sp[ i , "High_GR_Rollin" ]<-0
} else {
sp[ i , "High_GR_Rollin" ]<-(( mean(sp[,"Gr_High"][(i-100):i])))
}
}
Open_SD_Rollin<-NA
sp<-cbind(sp,Open_SD_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]>100)
{
sp[ i, "Open_SD_Rollin" ] <- sd(sp[,"Open"][(i-100):i])
}
}
Close_SD_Rollin<-NA
sp<-cbind(sp, Close_SD_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]>100)
{
sp[ i, "Close_SD_Rollin" ] <- sd(sp[,"Close"][(i-100):i])
}
}
Low_SD_Rollin<-NA
sp<-cbind(sp, Low_SD_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]>100)
{
sp[ i, "Low_SD_Rollin" ] <- sd(sp[,"Low"][(i-100):i])
}
}
High_SD_Rollin<-NA
sp<-cbind(sp, High_SD_Rollin)
for ( i in 2:nrow( sp ) ) {
if(sp[i,"nRows_in_sp"]>100)
{
sp[ i, "High_SD_Rollin" ] <- sd(sp[,"High"][(i-100):i])
}
}
N <- length(sp[,"Open"])
Openlag <- c(NA, sp[,"Open"][1:(N-1)])
sp<-cbind(sp,Openlag)
Highlag <- c(NA, sp[,"High"][1:(N-1)])
sp<-cbind(sp,Highlag)
Lowlag <- c(NA, sp[,"Low"][1:(N-1)])
sp<-cbind(sp,Lowlag)
Closelag <- c(NA, sp[,"Close"][1:(N-1)])
sp<-cbind(sp,Closelag)
Gr_Openlag <- c(NA, sp[,"Gr_Open"][1:(N-1)])
sp<-cbind(sp,Gr_Openlag)
Gr_Highlag <- c(NA, sp[,"Gr_High"][1:(N-1)])
sp<-cbind(sp,Gr_Highlag)
Gr_Lowlag <- c(NA, sp[,"Gr_Low"][1:(N-1)])
sp<-cbind(sp,Gr_Lowlag)
Gr_Closelag <- c(NA, sp[,"Gr_Close"][1:(N-1)])
sp<-cbind(sp,Gr_Closelag)
Gr_Volumelag <- c(NA, sp[,"Gr_Volume"][1:(N-1)])
sp<-cbind(sp,Gr_Volumelag)
Open_GR_Rollinlag <- c(NA, sp[,"Open_GR_Rollin"][1:(N-1)])
sp<-cbind(sp, Open_GR_Rollinlag)
Low_GR_Rollinlag <- c(NA, sp[,"Low_GR_Rollin"][1:(N-1)])
sp<-cbind(sp, Low_GR_Rollinlag)
High_GR_Rollinlag <- c(NA, sp[,"High_GR_Rollin"][1:(N-1)])
sp<-cbind(sp, High_GR_Rollinlag)
Close_GR_Rollinlag <- c(NA, sp[,"Close_GR_Rollin"][1:(N-1)])
sp<-cbind(sp, Close_GR_Rollinlag)
Open_SD_Rollinlag <- c(NA, sp[,"Open_SD_Rollin"][1:(N-1)])
sp<-cbind(sp, Open_SD_Rollinlag)
Low_SD_Rollinlag <- c(NA, sp[,"Low_SD_Rollin"][1:(N-1)])
sp<-cbind(sp, Low_SD_Rollinlag)
High_SD_Rollinlag <- c(NA, sp[,"High_SD_Rollin"][1:(N-1)])
sp<-cbind(sp, High_SD_Rollinlag)
Close_SD_Rollinlag <- c(NA, sp[,"Close_SD_Rollin"][1:(N-1)])
sp<-cbind(sp, Close_SD_Rollinlag)
OpenCoefs<-coefficients(summary(step(lm(sp[,"Open"] ~ Openlag + Lowlag + Highlag + Closelag + Gr_Openlag + Gr_Lowlag + Gr_Highlag + Gr_Closelag + Gr_Volumelag + Open_GR_Rollinlag + Low_GR_Rollinlag + High_GR_Rollinlag + Close_GR_Rollinlag + Open_SD_Rollinlag + Low_SD_Rollinlag + High_SD_Rollinlag + Close_SD_Rollinlag),direction="both",test="F")))
LowCoefs<-coefficients(summary(step(lm(sp[,"Low"] ~ Openlag + Lowlag + Highlag + Closelag + Gr_Openlag + Gr_Lowlag + Gr_Highlag + Gr_Closelag + Gr_Volumelag + Open_GR_Rollinlag + Low_GR_Rollinlag + High_GR_Rollinlag + Close_GR_Rollinlag + Open_SD_Rollinlag + Low_SD_Rollinlag + High_SD_Rollinlag + Close_SD_Rollinlag),direction="both",test="F")))
HighCoefs<-coefficients(summary(step(lm(sp[,"High"] ~ Openlag + Lowlag + Highlag + Closelag + Gr_Openlag + Gr_Lowlag + Gr_Highlag + Gr_Closelag + Gr_Volumelag + Open_GR_Rollinlag + Low_GR_Rollinlag + High_GR_Rollinlag + Close_GR_Rollinlag + Open_SD_Rollinlag + Low_SD_Rollinlag + High_SD_Rollinlag + Close_SD_Rollinlag),direction="both",test="F")))
CloseCoefs<-coefficients(summary(step(lm(sp[,"Close"] ~ Openlag + Lowlag + Highlag + Closelag + Gr_Openlag + Gr_Lowlag + Gr_Highlag + Gr_Closelag + Gr_Volumelag + Open_GR_Rollinlag + Low_GR_Rollinlag + High_GR_Rollinlag + Close_GR_Rollinlag + Open_SD_Rollinlag + Low_SD_Rollinlag + High_SD_Rollinlag + Close_SD_Rollinlag),direction="both",test="F")))
View(OpenCoefs)
View(LowCoefs)
View(HighCoefs)
View(CloseCoefs)
View(sp)

Answer 1

Your code is so bad, I had to take pity on you. :) Here's a refactored version of your code:
library(quantmod)
sp <- getSymbols("^GSPC", auto.assign=FALSE)
sp$GSPC.Adjusted <- NULL
colnames(sp) <- gsub("^GSPC\\.","",colnames(sp))
sp$Gr_Open <- ROC(Op(sp), type="discrete")
sp$Gr_High <- ROC(Hi(sp), type="discrete")
sp$Gr_Low <- ROC(Lo(sp), type="discrete")
sp$Gr_Close <- ROC(Cl(sp), type="discrete")
sp$Gr_Volume <- ROC(Vo(sp), type="discrete")
N <- 100
sp$Open_Rollin <- runMean(sp$Open, N)
sp$High_Rollin <- runMean(sp$High, N)
sp$Low_Rollin <- runMean(sp$Low, N)
sp$Close_Rollin <- runMean(sp$Close, N)
sp$Open_GR_Rollin <- runMean(sp$Gr_Open, N)
sp$High_GR_Rollin <- runMean(sp$Gr_High, N)
sp$Low_GR_Rollin <- runMean(sp$Gr_Low, N)
sp$Close_GR_Rollin <- runMean(sp$Gr_Close, N)
sp$Open_SD_Rollin <- runSD(sp$Open, N)
sp$High_SD_Rollin <- runSD(sp$High, N)
sp$Low_SD_Rollin <- runSD(sp$Low, N)
sp$Close_SD_Rollin <- runSD(sp$Close, N)
spLag <- lag(sp)
colnames(spLag) <- paste(colnames(sp),"lag",sep="")
sp <- na.omit(merge(sp, spLag))
There's no need to answer your first question in order to answer your second question. You don't have to cross-multiply coefficients with data by hand. You can simply access the fitted values from the model. That requires that you preserve the model though...
f <- Open ~ Openlag + Lowlag + Highlag + Closelag +
Gr_Openlag + Gr_Lowlag + Gr_Highlag + Gr_Closelag + Gr_Volumelag +
Open_GR_Rollinlag + Low_GR_Rollinlag + High_GR_Rollinlag + Close_GR_Rollinlag +
Open_SD_Rollinlag + Low_SD_Rollinlag + High_SD_Rollinlag + Close_SD_Rollinlag
OpenLM <- lm(f, data=sp)
HighLM <- update(OpenLM, High ~ .)
LowLM <- update(OpenLM, Low ~ .)
CloseLM <- update(OpenLM, Close ~ .)
OpenStep <- step(OpenLM,direction="both",test="F")
HighStep <- step(HighLM,direction="both",test="F")
LowStep <- step(LowLM,direction="both",test="F")
CloseStep <- step(CloseLM,direction="both",test="F")
tail(fitted(OpenStep),1)
# 2013-02-01
# 1497.91
tail(fitted(HighStep),1)
# 2013-02-01
# 1504.02
tail(fitted(LowStep),1)
# 2013-02-01
# 1491.934
tail(fitted(CloseStep),1)
# 2013-02-01
# 1499.851