setwd("c:/work/data scientist/course 4 - assignment 1/")

library( "sqldf" )

df <- read.csv.sql("household_power_consumption.txt", "select * from file where Date in ('1/2/2007', '2/2/2007')", sep=";")

df$DateTime <- strptime( paste( df$Date, df$Time ), format="%d/%m/%Y %H:%M:%S")

library( datasets )

png( file="plot3.png",width=480, height=480)

with( df, plot( DateTime, Sub_metering_1, type="n", main="", ylab="Energy sub metering", xlab=""))

with( df, lines( DateTime, Sub_metering_1, col="black"))

with( df, lines( DateTime, Sub_metering_2, col="red"))

with( df, lines( DateTime, Sub_metering_3, col="blue"))

legend("topright", lty=c(1,1), col = c("black", "red", "blue"), legend = c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"))

dev.off()