plot1.R

powcons <- read.table("C:/Users/zterjek/Desktop/household_power_consumption.txt", 
                      sep = ";", header = TRUE)

powercon <- subset(powcons, Date == "1/2/2007" | Date == "2/2/2007")

powercon$dt <- paste(powercon$Date, powercon$Time, sep = " ")
powercon$datetime <- strptime(powercon$dt, format = "%d/%m/%Y %H:%M")

powercon$Global_active_power <- as.numeric(powercon$Global_active_power)
powercon$Global_reactive_power <- as.numeric(powercon$Global_reactive_power)
powercon$Voltage <- as.numeric(powercon$Voltage)
powercon$Sub_metering_1 <- as.numeric(powercon$Sub_metering_1)
powercon$Sub_metering_2 <- as.numeric(powercon$Sub_metering_2)
powercon$Sub_metering_3 <- as.numeric(powercon$Sub_metering_3)

png(filename = "C:/Users/zterjek/Desktop/plot1.png", height = 480, width = 480)

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

dev.off()