Project Code and Comments.txt

# first save text file into working directory

# load the data into R
power <- read.table("household_power_consumption.txt", header = TRUE, sep = ";")

#subset data to get the rows that we want

power2 <- subset(power, Date == "1/2/2007" | Date == "2/2/2007", select = Date:Sub_metering_3)

#convert Global_active_power column from ÒfactorÓ to ÒnumericÓ class

power2$Global_active_power <- as.numeric(levels(power2$Global_active_power))[power2$Global_active_power]

# Create histogram (plot1)

hist(power2$Global_active_power, breaks=12, main = "Global Active Power", xlab = "Global Active Power (kilowatts)", col = "red")

#save plot1 as png file

png("plot1.png", width=480, height=480)

# merge the date and time fields

power2$Time <- strptime(paste(power2$Date,power2$Time),"%d/%m/%Y %H:%M:%S")



# create plot2

plot(power2$Time,power2$Global_active_power,type="l",xlab="Time",ylab="Global Active Power (kilowatts)")

# Convert Sub_metering_1 from ÒfactorÓ variable to ÒnumericÓ variable

power2$Sub_metering_1 <- as.numeric(levels(power2$Sub_metering_1))[power2$Sub_metering_1]

power2$Sub_metering_2 <- as.numeric(levels(power2$Sub_metering_2))[power2$Sub_metering_2]

power2$Sub_metering_3 <- as.numeric(levels(power2$Sub_metering_3))[power2$Sub_metering_3]



# Create plot 3
plot(power2$Time, power2$Sub_metering_1, type="l",xlab="Time",ylab="Energy sub metering")
lines(power2$Time, power2$Sub_metering_2, col="red")
lines(power2$Time, power2$Sub_metering_3, col="blue")

legend("topright",lty=c(1,1,1),col=c("black","red","blue"),legend=c("Sub_metering1","Sub_metering_2","Sub_metering_3"), cex=0.75)

# Change Voltage and Global_reactive_power to ÒnumericÓ variables

power2$Voltage <- as.numeric(levels(power2$Voltage))[power2$Voltage]
power2$Global_reactive_power <- as.numeric(levels(power2$Global_reactive_power))[power2$Global_reactive_power]



# Create plot 4

par(mfrow = c(2,2))
plot(power2$Time,power2$Global_active_power,type="l",xlab="Time",ylab="Global Active Power (kilowatts)")
plot(power2$Time,power2$Voltage,type="l",xlab="datetime",ylab="Voltage")
plot(power2$Time, power2$Sub_metering_1, type="l",xlab="Time",ylab="Energy sub metering")
lines(power2$Time, power2$Sub_metering_2, col="red")
lines(power2$Time, power2$Sub_metering_3, col="blue") plot(power2$Time,power2$Global_reactive_power,type="l",xlab="datetime",ylab="Global_reactive_power")