plot4.R

##Plot 4 - the quadruple plot.

##Reading dataset
powerr <- read.csv('/home/sara/Work/Courses/Coursera/Data_Science_Specialization/Course4/Week1/Course_project/data/household_power_consumption.txt', header = TRUE, sep = ";")

##Extracting the desired date range.
powerr2 = subset(powerr, powerr$Date == "1/2/2007" | powerr$Date == "2/2/2007")

##assigning the dataset as numeric and stripping away factors
powerr2$Sub_metering_1 <- as.numeric(as.character(powerr2$Sub_metering_1))
powerr2$Sub_metering_2 <- as.numeric(as.character(powerr2$Sub_metering_2))
powerr2$Sub_metering_3 <- as.numeric(as.character(powerr2$Sub_metering_3))

##assigning the dataset as character and stripping away factors
powerr2$Date3 <- as.character(powerr2$Date)
powerr2$Time3<- as.character(powerr2$Time)

##setting the time
powerr2$datetime <- strptime(paste(powerr2$Date3, powerr2$Time3), "%d/%m/%Y %H:%M:%S")

##preparing quadrouple plot.
par(mfrow = c(2,2))
par(mar = c(4,4,2,1))

plot (x= powerr2$datetime, y = powerr2$Global_active_power,
      ylab = 'Global Active power (kilowatts)',
      xlab ='  ',
      type = "l")

plot (x= powerr2$datetime, y = powerr2$Voltage,
      ylab = 'Voltage',
      xlab ='datetime',
      type = "l")

plot (x= powerr2$datetime, y = powerr2$Sub_metering_1,
      ylab = 'Energy sub metering',
      xlab ='  ',
      type = "l")
legend("topright" , bty = "n", lty = 1, col = c("black","red","blue"), legend = c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"))
lines(x= powerr2$datetime, y = powerr2$Sub_metering_2, col = "red")
lines(x= powerr2$datetime, y = powerr2$Sub_metering_3, col = "blue")

plot (x= powerr2$datetime, y = as.numeric(powerr2$Global_reactive_power),
      ylab = 'Global_reactive_power',
      xlab ='datetime',
      #ylim = range(0,0.5),
      type = "l")

dev.off()