plot1.R

# check if a data folder exists; if not then create one
if (!file.exists("data")) {
	dir.create("data")
}

# file URL & destination file
fileUrl <- "https://d396qusza40orc.cloudfront.net/exdata%2Fdata%2Fhousehold_power_consumption.zip"
destfile <- "./data/power_consumption.zip"

# download the file & note the time
download.file(fileUrl, destfile)
dateDownloaded <- date()

# set the file to read
d <- file("./data/household_power_consumption.txt", "r");

# read in the data until date
dados <- read.table(text = grep("^[1,2]/2/2007", readLines(d), value = TRUE),
sep = ";", skip = 0, na.strings = "?", stringsAsFactors = FALSE)

# rename the columns
names(dados) <- c("date", "time", "active_power", "reactive_power", "voltage",
"intensity", "sub_metering_1", "sub_metering_2",
"sub_metering_3")

# add a new date-time formated column
dados$new_time <- as.POSIXct(paste(dados$date, dados$time), format = "%d/%m/%Y %T")

# plot 1 - histogram
par(mfrow = c(1, 1))
hist(data_$active_power, main = "Global Active Power", xlab = "Global Active 
Power (kilowatts)", ylab = "Frequency", col = "red", freq = TRUE)

# copy plot to png file
dev.copy(png, file = "plot1.png")

# close connection to png device
dev.off()