plot3.R

rm(list=ls())

#please copy the file with the name "household_power_consumption.txt" in a directory of your choice.
#everything else runs automatically.

#initialize:
setwd("C:/Users/Dimitrios/Documents/R")
HouseholdData <- as.data.frame(read.csv("household_power_consumption.txt", sep=";", header = TRUE))
head(HouseholdData)

#the date format is: DD/MM/YYYY:
HouseholdDataToUse <- subset(HouseholdData, HouseholdData$Date=="1/2/2007" | HouseholdData$Date=="2/2/2007")

#making sure that we do not have any missing values denoted by "?":
HouseholdDataToUse <- subset(HouseholdDataToUse, HouseholdDataToUse$Global_active_power!="?" & HouseholdDataToUse$Date!="?" & HouseholdDataToUse$Time!="?")

#create datetime column just by pasting two columns:
HouseholdDataToUse$datetime<- paste(HouseholdDataToUse$Date,HouseholdDataToUse$Time)

#opening file:
png(filename = "plot3.png", width = 480, height = 480)

#plot: everything controlled by myself, the x-axis range and what will be shown on it.
#removing x-label also:
plot(as.integer(as.factor(paste(HouseholdDataToUse$Date, HouseholdDataToUse$Time))),as.numeric(HouseholdDataToUse$Sub_metering_1),type="l", xaxt="n", xlab = "",ylab="Energy sub metering")
lines(as.integer(as.factor(paste(HouseholdDataToUse$Date, HouseholdDataToUse$Time))),as.numeric(HouseholdDataToUse$Sub_metering_2),type="l",col="red", xaxt="n", xlab = "")
lines(as.integer(as.factor(paste(HouseholdDataToUse$Date, HouseholdDataToUse$Time))),as.numeric(HouseholdDataToUse$Sub_metering_3),type="l",col="blue", xaxt="n", xlab = "")

legend("topright", pch = 1, col = c("black", "red", "blue"), legend = c("Sub Metering 1", "Sub Metering 2", "Sub Metering 3"))

#putting the dates in 0 seconds, 1440 seconds (1 day) and 2880 seconds (2 days):
axis(1, at=(c(0,1440,2880)), labels=c("Thu","Fri", "Sat"))

dev.off()