plot2.R

#Loading data from a txt file
#na symbol is "?", decimal separator is ".", field separator is ";" 
data<-read.table("D:/Eugene/R/hh power/household_power_consumption.txt",dec=".",sep=";",na.strings="?",header=T)

#Converting dates to date type
data$Date<-as.Date(data$Date,"%d/%m/%Y")

#Subsetting 
data1<-data[data$Date=="2007-02-01"|data$Date=="2007-02-02",]

# combining date and time
data1$DateTime <- as.POSIXct(paste(data1$Date, data1$Time))

# Plotting
png("plot2.png", width=480, height= 480)
plot(data1$DateTime, data1$Global_active_power, type= "l", lwd=1, ylab= "Global Active Power (kilowatts)", xlab="")
dev.off()