plot2.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("plot2.png",width=480,height=480)
plot(d2$rTime,d2$Global_active_power,type="l",xlab="",ylab="Global Active Power(kilowatts)")


dev.off()