## install and load xlsx package
if (!require(xlsx)) install.packages('xlsx')
library("xlsx")

## input data from .xlsx file into R working space
testdata <- read.xlsx("C:/testdata.xlsx", sheetName="Sheet1")
names(testdata)
dim(testdata)

## output R results into new .xlsx file
write.xlsx(testresult$timeset, file="C:/testresult.xlsx", sheetName="timeset")
write.xlsx(testresult$sharpe.ratio, file="C:/testresult.xlsx", sheetName="sharpe.ratio", append=TRUE)
write.xlsx(testresult$weight, file="C:/testresult.xlsx", sheetName="weight", append=TRUE)

## save plot in the screen
savePlot("myplot.png")