Date1 <- strptime("01/02/2007","%d/%m/%Y") # first date in data to analyse

Date2 <- strptime("02/02/2007","%d/%m/%Y") # second date in data to analyse

## Read whole data

data <- read.csv2("household_power_consumption.txt",

stringsAsFactors = FALSE,

na.strings = "?")

## use only data for specified dates

data <- data[strptime(data$Date, "%d/%m/%Y") == Date1 |

strptime(data$Date, "%d/%m/%Y") == Date2,]

png(file="plot1.png") ## open png device

hist(as.double(data$Global_active_power), ## convert text to double

main="Global Active Power", ## main heading

xlab = "Global Active Power (kilowatts)", ## x-axis text

ylab = "Frequency", ## y-axis text

border = NULL, ## no border lines

col="red") ## color of bars

dev.off() ## close device