plot4.R

library(dplyr)
source("loadData.R")
data <- load_data()

png("plot4.png", width=480,height=480)
par(mfrow=c(2,2))
plot(data$datetime, data$Global_active_power, type = "l", ylab="Global Active Power", xlab = "")
plot(data$datetime, data$Voltage, type = "l", ylab="Voltage", xlab = "datetime")
plot(data$datetime, data$Sub_metering_1, type = "l", ylab="Energy sub metering", xlab = "")
lines(data$datetime, data$Sub_metering_2, type = "l", col="red")
lines(data$datetime, data$Sub_metering_3, type = "l", col="blue")
legend("topright", legend=c("Sub_metering_1","Sub_metering_2","Sub_metering_3"), col=c("black","red","blue"), lty = 1)
plot(data$datetime, data$Global_reactive_power, type = "l", ylab="Global_reactive_power", xlab = "datetime")
dev.off()

rm(list=ls())