add ploting script

implements R code to generate plots,
adds plots to repo

plot1.R

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+# read data
+data_ <- read.table("household_power_consumption.txt", sep = ";", na.strings = "?", header = T);
+# Convert date and time
+data_$Time <- strptime(x = paste(data_$Date, data_$Time, sep = " "), format = "%d/%m/%Y %H:%M:%S")
+data_$Date <- as.Date(data_$Date,format = '%d/%m/%Y')
+
+start_ <- as.Date("2007-02-01")
+end_ <- as.Date("2007-02-02")
+
+data2 <- data_[which(data_$Date >= start_ & data_$Date <= end_),]
+
+# draw plot 1
+png(file = "plot1.png", width = 480, height = 480, units = "px")
+
+hist(data2$Global_active_power, 
+     main="Global Active Power", 
+     xlab="Global Active Power (kilowatts)",
+     col="red")
+
+dev.off()

plot2.R

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+# read data
+data_ <- read.table("household_power_consumption.txt", sep = ";", na.strings = "?", header = T);
+# Convert date and time
+data_$Time <- strptime(x = paste(data_$Date, data_$Time, sep = " "), format = "%d/%m/%Y %H:%M:%S")
+data_$Date <- as.Date(data_$Date,format = '%d/%m/%Y')
+
+start_ <- as.Date("2007-02-01")
+end_ <- as.Date("2007-02-02")
+
+data2 <- data_[which(data_$Date >= start_ & data_$Date <= end_),]
+
+# draw plot 2
+png(file = "plot2.png", width = 480, height = 480, units = "px")
+
+plot(
+  x = data2$Time,
+  y = data2$Global_active_power,
+  type = "l",
+  xlab="",
+  ylab="Global Active Power (kilowatts)"
+)
+
+dev.off()

plot3.R

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+# read data
+data_ <- read.table("household_power_consumption.txt", sep = ";", na.strings = "?", header = T);
+# Convert date and time
+data_$Time <- strptime(x = paste(data_$Date, data_$Time, sep = " "), format = "%d/%m/%Y %H:%M:%S")
+data_$Date <- as.Date(data_$Date,format = '%d/%m/%Y')
+
+start_ <- as.Date("2007-02-01")
+end_ <- as.Date("2007-02-02")
+
+data2 <- data_[which(data_$Date >= start_ & data_$Date <= end_),]
+
+# draw plot 3
+png(file = "plot3.png", width = 480, height = 480, units = "px")
+
+plot(
+  x = data2$Time,
+  y = data2$Sub_metering_1,
+  type = "l",
+  xlab="",
+  ylab="Energy sub metering"
+)
+
+lines(
+  x=data2$Time,
+  y=data2$Sub_metering_2,
+  col="red")
+
+lines(
+  x=data2$Time,
+  y=data2$Sub_metering_3,
+  col="blue")
+
+legend("topright",c("Sub_metering_1","Sub_metering_2","Sub_metering_3"),bty="l",col=c("black","red","blue"),lwd=2,cex=0.7)
+
+dev.off()

plot4.R

@@ -0,0 +1,64 @@
+# read data
+data_ <- read.table("household_power_consumption.txt", sep = ";", na.strings = "?", header = T);
+# Convert date and time
+data_$Time <- strptime(x = paste(data_$Date, data_$Time, sep = " "), format = "%d/%m/%Y %H:%M:%S")
+data_$Date <- as.Date(data_$Date,format = '%d/%m/%Y')
+
+start_ <- as.Date("2007-02-01")
+end_ <- as.Date("2007-02-02")
+
+data2 <- data_[which(data_$Date >= start_ & data_$Date <= end_),]
+
+# draw plot 4
+png(file = "plot4.png", width = 480, height = 480, units = "px")
+
+par(mfrow=c(2,2))
+# 1
+plot(
+  x = data2$Time,
+  y = data2$Global_active_power,
+  type = "l",
+  xlab="",
+  ylab="Global Active Power"
+)
+
+# 2
+plot(
+  x = data2$Time,
+  y = data2$Voltage,
+  type = "l",
+  xlab="datetime",
+  ylab="Voltage"
+)
+
+# 3
+plot(
+  x = data2$Time,
+  y = data2$Sub_metering_1,
+  type = "l",
+  xlab="",
+  ylab="Energy sub metering"
+)
+
+lines(
+  x=data2$Time,
+  y=data2$Sub_metering_2,
+  col="red")
+
+lines(
+  x=data2$Time,
+  y=data2$Sub_metering_3,
+  col="blue")
+
+legend("topright",c("Sub_metering_1","Sub_metering_2","Sub_metering_3"),bty="l",col=c("black","red","blue"),lwd=2,cex=0.7)
+
+# 4
+plot(
+  x = data2$Time,
+  y = data2$Global_reactive_power,
+  type = "l",
+  xlab="datetime",
+  ylab="Global_reactive_power"
+)
+
+dev.off()