Plot3.R

> library("data.table")
> setwd("C:/R/4_Exploratory_DATA")
> #Reads in data from file then subsets data for specified dates
> powerDT <- data.table::fread(input = "household_power_consumption.txt"
+                              , na.strings="?"
+ )
> # Prevents Scientific Notation
> powerDT[, Global_active_power := lapply(.SD, as.numeric), .SDcols = c("Global_active_power")]
> # Making a POSIXct date capable of being filtered and graphed by time of day
> powerDT[, dateTime := as.POSIXct(paste(Date, Time), format = "%d/%m/%Y %H:%M:%S")]
> # Filter Dates for 2007-02-01 and 2007-02-02
> powerDT <- powerDT[(dateTime >= "2007-02-01") & (dateTime < "2007-02-03")]
> png("plot3.png", width=480, height=480)
> # Plot 3
> plot(powerDT[, dateTime], powerDT[, Sub_metering_1], type="l", xlab="", ylab="Energy sub metering")
> lines(powerDT[, dateTime], powerDT[, Sub_metering_2],col="red")
> lines(powerDT[, dateTime], powerDT[, Sub_metering_3],col="blue")
> legend("topright"
+        , col=c("black","red","blue")
+        , c("Sub_metering_1  ","Sub_metering_2  ", "Sub_metering_3  ")
+        ,lty=c(1,1), lwd=c(1,1))
> dev.off()
null device 
          1 
>