plot4.R

### PLOT 4 ###

library(data.table)

## Getting the entire dataset : Electric power consumption
data_entire <- fread("/Users/salimahmokhtar/household_power_consumption.txt", na.strings="?")

## Subsetting the data from the dates 2007-02-01 and 2007-02-02
data_entire$Date <- as.Date(data_entire$Date, format="%d/%m/%Y")
data <- subset(data_entire, subset=(Date >= "2007-02-01" & Date <= "2007-02-02"))
rm(data_entire)

## Converting dates
datetime <- paste(as.Date(data$Date), data$Time)
data$Datetime <- as.POSIXct(datetime)

#Output plot 4 to png
png(filename="plot4.png", width=480, height=480)

par(mfrow=c(2,2), mar=c(4,4,2,1), oma=c(0,0,2,0))
with(data, {
  plot(Global_active_power ~ Datetime, type="l", 
       ylab="Global Active Power", xlab="")
  plot(Voltage ~ Datetime, type="l", 
       ylab="Voltage", xlab="datetime")
  plot(Sub_metering_1 ~ Datetime, type="l", 
       ylab="Energy Sub Meteringr", 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, bty="n",
         legend=c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"))
  plot(Global_reactive_power ~ Datetime, type="l", 
       ylab="Global_reactive_power",xlab="datetime") }
)
dev.off()