plot4.R

plot4 <- function ( wd = "C:/f/R/git/ExData_Plotting1", datefrom = "31/1/2007" , dateto = "3/2/2007"  ,...)
{
  setwd( wd)
  directory <- "exdata_data_household_power_consumption"
  fn <- "household_power_consumption.txt"
  filen <- file.path (directory, fn)
  conn <- file ( filen , "r")
  data<-read.table (conn , header=  TRUE , sep= ";" ,na.strings="?")
  close(conn)
  
  #######################################################################
  
  ## filter required data 
  data07 <- data[ as.Date(data$Date ,"%d/%m/%Y") > as.Date(datefrom ,"%d/%m/%Y") &  
                    as.Date(data$Date,"%d/%m/%Y") < as.Date(dateto,"%d/%m/%Y") ,]
  Data<- NULL
  data07$datetime<- as.POSIXct(strptime(paste(data07$Date, data07$Time), "%d/%m/%Y %H:%M:%S"))
  
  ##data$datetime <- paste(data$Date, data$Time)
  ##data$datetime<- as.Date(strptime(data$datetime,"%d/%m/%Y %H:%M:%S"  )) 
  data07$Global_active_power  <- as.numeric( data07$Global_active_power)
  
  #######################################################################
  ## plot4
  
  par( mfrow = c( 2,2))
  RR<- with (data07 , { plot(   data07$datetime ,data07$Global_active_power/1000   , type ="l" , xlab= " "  , ylab = "Global Active Power"   ) 
                        plot(   data07$datetime ,data07$Voltage   , type ="l" , xlab= " DateTime " ,ylab = "Voltage"  ) 
                        plot(   data07$datetime ,data07$Sub_metering_1  , type ="l" , xlab= "  " ,ylab = "energy sub-metering" ,col = 'black'  ) 
                        with (data07 , points (  data07$datetime ,data07$Sub_metering_2  , col = 'red' , type ="l" ))
                        with (data07 , points (  data07$datetime ,data07$Sub_metering_3  , col = 'blue' , type ="l" ))
                        plot(   data07$datetime ,data07$Global_reactive_power   , type ="l" , xlab= " DateTime " ,ylab = "Global ReActive Power"  ) 
  }
  )
  ## coping output to png file "plot4.png"
  dev.copy(png,filename="plot4.png" , height=480, width=480);
  dev.off()
  
  return(RR)
  
}