plot1.R

# Plot 1

library(dplyr)

zipfile <- "exdata_household_power_consumption.zip"
textfile <- "household_power_consumption.txt"

# Check if we have already downloaded the file. If not, lets grab it.
if(!file.exists(zipfile)) {
        download.file("https://d396qusza40orc.cloudfront.net/exdata%2Fdata%2Fhousehold_power_consumption.zip"
                      ,zipfile)
}

# Unzip the file and read in the data
unzip(zipfile, textfile)
householddata <- read.csv(textfile, na.strings = "?", sep=";",
        stringsAsFactors = FALSE, 
        colClasses = c(rep("character",2),rep("numeric",7)))

# Change the date
householddata <- mutate(householddata, Date = as.Date(Date,"%d/%m/%Y"))

# Filter
householddata <- filter(householddata, Date == "2007-02-01" | Date == "2007-02-02")

png(filename = "plot1.png",
    width = 480, height = 480, units = "px")
hist(householddata$Global_active_power, main = "Global Active Power", 
     xlab="Global Active Power (kilowatts)"
     , col="red")
dev.off()