plot4.R

#20150112
#marklittle
#setwd("D:\\Rѧϰ±Ê¼Ç\\Exploratory Data Analysis\\week 1")
#fileURL<-"https://d396qusza40orc.cloudfront.net/exdata%2Fdata%2Fhousehold_power_consumption.zip"
#download.file(fileURL,destfile="./t1.zip",method="curl",extra="-k")

library(dplyr)
print("--------------")
d1<-read.table("household_power_consumption.txt",colClasses=c("character","character","character","character","character","character","character","character","character"),header=TRUE,sep=";")#


c1<-paste(d1$Date, d1$Time)

c2<-strptime(c1, "%d/%m/%Y %H:%M:%S")

d1<-cbind(d1,rDate=as.Date(c2),rTime=c2)

d2<-subset(d1,subset=(rDate =="2007-02-01" |rDate =="2007-02-02" ))


png("plot4.png",width=480,height=480)
par(mfrow=c(2,2))
with(d2,	plot(rTime,Global_active_power,type="l",xlab="",ylab="Global Active Power",col="black"))
with(d2,	 plot(rTime,Voltage,type="l",xlab="",ylab="Voltage",col="black",sub="datetime")	)
with(d2,{plot(rTime,Sub_metering_1,type="l",xlab="",ylab="Energy sub metering",col="black")	
lines(rTime,Sub_metering_2,type="l",col="red")
lines(rTime,Sub_metering_3,type="l",col="blue")	
legend("topright",lty=1,col=c("black","red","blue"),legend=c("sub_metering_1","sub_metering_2","sub_metering_3"))})
with(d2,	 plot(rTime,Global_reactive_power,type="l",xlab="",ylab="Global_reactive_power",col="black",sub="datetime"))

dev.off()