workdir <- "C:/Users/aahumada.SA/MatLab/RStudio/ExData_Plotting1"

src1 <- paste(workdir,"household_power_consumption.txt" , sep = "/")

setwd(workdir)

#------------------------------------------

# LOAD DATA SOURCE

#------------------------------------------

# Date : Date in format dd/mm/yyyy

# Time : time in format hh:mm:ss

# Global_active_power : household global minute-averaged active power (in kilowatt)

# Global_reactive_power : household global minute-averaged reactive power (in kilowatt)

# Voltage : minute-averaged voltage (in volt)

# Global_intensity : household global minute-averaged current intensity (in ampere)

# Sub_metering_1 : energy sub-metering No. 1 (in watt-hour of active energy).

# It corresponds to the kitchen, containing mainly a dishwasher,

# an oven and a microwave (hot plates are not electric but gas powered).

# Sub_metering_2 : energy sub-metering No. 2 (in watt-hour of active energy).

# It corresponds to the laundry room, containing a washing-machine,

# a tumble-drier, a refrigerator and a light.

# Sub_metering_3 : energy sub-metering No. 3 (in watt-hour of active energy).

# It corresponds to an electric water-heater and an air-conditioner.

#------------------------------------------

# EXAMPLE

#------------------------------------------

# Date;Time;Global_active_power;Global_reactive_power;Voltage;Global_intensity;Sub_metering_1;Sub_metering_2;Sub_metering_3

# 16/12/2006;17:24:00;4.216;0.418;234.840;18.400;0.000;1.000;17.000

data <- read.table(src1

, header=TRUE

, sep=";"

, colClasses = "character"

)

#

# Generate datetime, convert to date and numeric

#

data$dt <- strptime(paste(data[,1],data[,2]),"%d/%m/%Y %H:%M:%S")

data[,1] <- as.Date( data[,1], "%d/%m/%Y")

for ( i in c(3:9) ) { data[,i] <- as.numeric(data[,i]) }

#

# Subset from 2007-02-01 to 2007-02-02

#

d.ini <- as.Date("2007-02-01")

d.end <- as.Date("2007-02-02")

cond <- data$Date >= d.ini & data$Date <= d.end

#------------------------------------------

# DRAW GRAPHICS

#------------------------------------------

png( file ="plot2.png"

,width = 504

,height = 504

,bg = "transparent"

)

opar <- par(no.readonly=TRUE)

with(subset(data, cond ) , {

plot(dt, Global_active_power

, type="l"

, ann=FALSE

)

title( ylab="Global Active Power (kilowatts)" )

}

)

par(opar)

dev.off() ## Don't forget to close the PNG device!