Hotel <- function(hotel) {

require(data.table)

dat <- read.csv("demo.csv", header = TRUE)

dat$Date <- as.Date(paste0(format(strptime(as.character(dat$Date), 
                                       "%m/%d/%y"), 
                                      "%Y/%m"),"/1"))

library(data.table)
table <- setDT(dat)[, list(Revenue = sum(Revenues),
              Hours = sum(Hours),
              Index = mean(Index)), 
              by = list(Hotel, Date)]


  answer <- na.omit(table[table$Hotel == hotel, ])

  if (nrow(answer) == 0) {
  stop("invalid hotel")
  }

  return(answer)
  }
	
#Reads the dataframe from the Hotel Function
star <- (Hotel("Hotel Name"))
	
#Calculates the Revpar and Index
Revpar <- star$Revenue / star$Rooms
Index <- star$Index

png(filename = "~/Desktop/result.png", width = 480, height= 480)
plot(Index, Revpar, main = "Hotel Name", col = "green", pch = 20)

testing <- cor.test(Index, Revpolu)

write.table(testing[["p.value"]], file = "output.csv", sep = ";", row.names = FALSE, col.names = FALSE)
dev.off()