This assignment uses data from the UC Irvine Machine Learning Repository. In particular, the "Individual household electric power consumption Data Set" is used:

• Dataset: Electric power consumption [20Mb]

• Description: Measurements of electric power consumption in one household with a one-minute sampling rate over a period of almost 4 years. Different electrical quantities and some sub-metering values are available.

The following descriptions of the 9 variables in the dataset are taken from the UCI web site:

1. Date: Date in format dd/mm/yyyy
2. Time: time in format hh:mm:ss
3. Global_active_power: household global minute-averaged active power (in kilowatt)
4. Global_reactive_power: household global minute-averaged reactive power (in kilowatt)
5. Voltage: minute-averaged voltage (in volt)
6. Global_intensity: household global minute-averaged current intensity (in ampere)
7. 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).
8. 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.
9. 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.

• The time frame used for analysis is 2007-02-01 and 2007-02-02.

• The generated plots are PNG files with a width of 480 pixels and a height of 480 pixels.

• The plots are "plot1.png", "plot2.png", "plot3.png", "plot3.png" and "plot4.png"

• The corresponding scripts are "plot1.R", "plot2.R", "plot3.R", "plot3.R" and "plot4.R"

• The scripts assume the data txt file is contained in the same dorectiry as the scripts.

• The scripts generate PNG plots into the same folder as scripts.