Added plot4.R and plot4.png and modified previous R scripts so that t…

…he generated PNG has a transparent background

plot1.R

@@ -23,6 +23,6 @@ dateUntil <- as.POSIXct("03/02/2007 00:00:00", format="%d/%m/%Y %H:%M:%S")
 data <- filter(data, DateAndTime >= dateFrom & DateAndTime < dateUntil)
 
 # Plot it into a png file
-png(file = "plot1.png", width = 480, height = 480)
+png(file = "plot1.png", width = 480, height = 480, bg = "transparent")
 hist(data$Global_active_power, col = "red", main = "Global Active Power", xlab = "Global Active Power (kilowatts)")
 dev.off()

plot2.R

@@ -23,7 +23,7 @@ dateUntil <- as.POSIXct("03/02/2007 00:00:00", format="%d/%m/%Y %H:%M:%S")
 data <- filter(data, DateAndTime >= dateFrom & DateAndTime < dateUntil)
 
 # Plot it into a png file
-png(file = "plot2.png", width = 480, height = 480)
+png(file = "plot2.png", width = 480, height = 480, bg = "transparent")
 with(data, plot(DateAndTime, Global_active_power, type = "l", xlab = "", ylab = "Global Active Power (kilowatts)"))
 dev.off()
 

plot3.R

@@ -23,7 +23,7 @@ dateUntil <- as.POSIXct("03/02/2007 00:00:00", format="%d/%m/%Y %H:%M:%S")
 data <- filter(data, DateAndTime >= dateFrom & DateAndTime < dateUntil)
 
 # Plot it into a png file
-png(file = "plot3.png", width = 480, height = 480)
+png(file = "plot3.png", width = 480, height = 480, bg = "transparent")
 with(data, {plot(DateAndTime, Sub_metering_1, type = "n", xlab = "", ylab = "Energy sub metering");
             lines(DateAndTime, Sub_metering_1, col = "black");
             lines(DateAndTime, Sub_metering_2, col = "red");

plot4.R

@@ -0,0 +1,51 @@
+# Data downloading and reading
+fileURL<-"https://d396qusza40orc.cloudfront.net/exdata%2Fdata%2Fhousehold_power_consumption.zip"
+download.file(fileURL, destfile="./exdata-data-household_power_consumption.zip", method="curl")
+unzip("exdata-data-household_power_consumption.zip")
+conn <- file("household_power_consumption.txt", "r")
+
+data <- read.table(conn, 
+                   sep = ";", 
+                   comment.char = "", 
+                   na.strings = "?",
+                   header = TRUE, 
+                   colClasses = c("character", "character", "numeric", "numeric", "numeric", "numeric", "numeric", "numeric", "numeric"))
+
+#Convert Date and Time into one single DateAndTime variable
+data$DateAndTime <- as.POSIXct(paste(data$Date, data$Time), format="%d/%m/%Y %H:%M:%S")
+data$Time <- NULL
+data$Date <- NULL
+
+#Subset the dataset to the following date range: 2007-02-01 and 2007-02-02
+libary(dplyr)
+dateFrom <- as.POSIXct("01/02/2007 00:00:00", format="%d/%m/%Y %H:%M:%S")
+dateUntil <- as.POSIXct("03/02/2007 00:00:00", format="%d/%m/%Y %H:%M:%S")
+data <- filter(data, DateAndTime >= dateFrom & DateAndTime < dateUntil)
+
+# Plot it into a png file
+png(file = "plot4.png", width = 480, height = 480, bg = "transparent")
+
+par(mfrow = c(2, 2), mar = c(5,4,3,2))
+
+# Topleft plot
+
+with(data, plot(DateAndTime, Global_active_power, type = "l", xlab = "", ylab = "Global Active Power"))
+
+# Topright plot
+
+with(data, plot(DateAndTime, Voltage, type = "l", xlab = "datetime"))
+
+# Bottomleft plot
+
+with(data, {plot(DateAndTime, Sub_metering_1, type = "n", xlab = "", ylab = "Energy sub metering");
+            lines(DateAndTime, Sub_metering_1, col = "black");
+            lines(DateAndTime, Sub_metering_2, col = "red");
+            lines(DateAndTime, Sub_metering_3, col = "blue");
+            legend("topright", col = c("black", "red", "blue"), lwd = 1, bty = "n", legend = c("Sub_metering_1","Sub_metering_2","Sub_metering_3"))})
+
+# Bottomright plot
+
+with(data, plot(DateAndTime, Global_reactive_power, type = "l", xlab = "datetime"))
+
+
+dev.off()