data=read.table("household_power_consumption.txt",header=TRUE,sep=";") #reads the file "household_power_consumption.txt" data$Date<-as.Date(data$Date,format="%d/%m/%Y") #reads the "Date" column as a Date with a defined format dias<-data[(data$Date=="2007-02-01")|(data$Date=="2007-02-02"),] #Selects two specific dates from "Dates" and generates a new data frame named "dias" dias$Global_active_power<-as.numeric(as.character(dias$Global_active_power)) #converts the "Global_active_power" from "factor" to "character" and finally to "numeric" from "dias" dias$Global_reactive_power<-as.numeric(as.character(dias$Global_reactive_power)) # Does the same to "Global_reactive_power" from "dias" dias$Voltage<-as.numeric(as.character(dias$Voltage)) # Extracts the "Voltage" information from "dias" and converts it to numeric dias<-transform(dias,timestamp=as.POSIXct(paste(Date,Time)), "%d/%m/%Y %H:%M:%s") # POSIXct gives the possibility to make calculations with the variables "Date" and "Time" for future calculations dias$Sub_metering_1<-as.numeric(as.character(dias$Sub_metering_1)) dias$Sub_metering_2<-as.numeric(as.character(dias$Sub_metering_2)) dias$Sub_metering_3<-as.numeric(as.character(dias$Sub_metering_3))

plot1<-function(){ hist(dias$Global_active_power,main="Global Active Power",col="lightblue",xlab="Global Active Power (kilowatts)") # Creates a histogram of the distribution of consumption (in kilowatts) of "Global Active Power" dev.copy(png,file="plot1.png",width=480,height=480) # Generates the previous histogram in a png format, named "plot1.png" with a fixed width and height dev.off() # Saves and closes the window (of the .png file generation) cat("Plot 1 is saved in your directory",getwd()) # Sends a message to user about the plot1.png file } # Closes the function plot1 plot1() # Calls plot1

plot2<-function(){ plot(dias$timestamp,dias$Global_active_power,type="l",xlab="",ylab="Global Active Power (kilowatts)") dev.copy(png,file="plot2.png",width=480,height=480) dev.off cat("plot2.png is saved in you directory",getwd()) } plot2()

plot3<-function(){ plot(dias$timestamp,dias$Sub_metering_1,type="l",xlab="",ylab="Energy sub metering") lines(dias$timestamp,dias$Sub_metering_2,col="red") lines(dias$timestamp,dias$Sub_metering_3,col="blue") legend("topright",col=c("black","red","blue"),c("Sub_metering_1 ","Sub_metering_2 ","Sub_metering_3 "),lty=c(1,1),lwd=c(1,1)) dev.copy(png,file="plot3.png",width=480,height=480) dev.off() cat("plot3.png is saved in your directory",getwd()) } plot3()

plot4<-function(){ par(mfrow=c(2,2)) plot(dias$timestamp,dias$Global_active_power,type="l",xlab="",ylab="Global Active Power") plot(dias$timestamp,dias$Voltage,type="l",xlab="Datetime",ylab="Voltage") plot(dias$timestamp,dias$Sub_metering_1,type="l",xlab="",ylab="Energy sub metering") lines(dias$timestamp,dias$Sub_metering_2,col="red") lines(dias$timestamp,dias$Sub_metering_3,col="blue") legend("topright",col=c("black","red","blue"),c("Sub_metering_1 ","Sub_metering_2 ","Sub_metering_3 "),lty=c(1,1),bty="n",cex=0.5) plot(dias$timestamp,dias$Global_active_power,type="l",xlab="Datetime",ylab="Global_active_power") dev.copy(png,file="plot4.png",width=480,height=480) dev.off() cat("plot4.png is saved",getwd()) } plot4()