1Proj2Plot3.R

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# Author: Carolyn Clayton
# Date: 2015/01/08
# Exploratory Data Analysis: Project 1: Plot 3
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# IMPORT AND FORMAT VARIABLES
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require(checkpoint)
checkpoint(snapshot = "2014-12-01", project = getwd(), verbose = T)
require(data.table)
data <- fread("household_power_consumption.txt", na.strings = c("?", "NA", ""), verbose = TRUE)
data$Date <- as.Date(data$Date, format = "%d/%m/%Y")
data <- data[data$Date >= "2007-02-01" & data$Date <= "2007-02-02"]
data$Global_active_power <- as.numeric(data$Global_active_power)
data$DateTime <- as.POSIXct(paste(as.character(data$Date),as.character(data$Time)))

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# PLOT 3
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par(bg = "white")
with(data, plot(DateTime, Sub_metering_1, ylab = "Energy sub metering", xlab = "", type = "n"))
with(data, lines(DateTime, Sub_metering_1, col = "black"))
with(data, lines(DateTime, Sub_metering_2, col = "red"))
with(data, lines(DateTime, Sub_metering_3, col = "blue"))
legend("topright", lty = c(1, 1, 1), col = c("black", "red", "blue"), legend = c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"), cex=0.8, text.width = strwidth("Sub_metering_1"))
dev.copy(png, file = "plot3.png")
dev.off()