plot3.R

# Getting data
filename = "household_power_consumption.txt"
data <- read.table(filename,header = T, sep=";",stringsAsFactors = F, na.strings="?", nrows=2075259)

# Subset by dates
dataSubset <- subset(data, strptime(Date, format="%d/%m/%Y") >= strptime("2007-02-01", format="%Y-%m-%d") 
                     & strptime(Date, format="%d/%m/%Y") <= strptime("2007-02-02", format="%Y-%m-%d"))

dateTime <- paste(as.Date(dataSubset$Date, "%d/%m/%Y"), dataSubset$Time)
dataSubset$Datetime <- as.POSIXct(dateTime)

# Plot
png(filename = "plot3.png", width = 480, height = 480)
with(dataSubset, {
  plot(Sub_metering_1~Datetime, type="l",
       ylab="Energy sub metering", xlab="")
  lines(Sub_metering_2~Datetime,col='Red')
  lines(Sub_metering_3~Datetime,col='Blue')
})
legend("topright", col=c("black", "red", "blue"), lty=1, lwd=2, 
       legend=c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"))


dev.off()