Project assignment for the Getting and Cleaning Data course.

This file explains how to use the run_analysis.R script to extract a simplified and cleaner data table out of the Human Activity Recognition Using Smartphones data set described at http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones

You should place the run_analysis.R in the folder you will use for the analysis and set this folder as the current folder of the R session by using the setwd(dir) function, then load the script with the source function :

source("run_analysis.R")

This will define two new functions :

• downloadRawDataFile()
• generateTidyDataFile()

There are two options to retrieve the raw data set :

• You can run :

downloadRawDataFile()

to automaticaly download the zip file from https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip into a UCI HAR Dataset.zip file in the current folder, or

• download the zip file yourself and put it in the current folder.

When you have the zip file of the raw data set in the current folder you can generate the tidy data set by running the generateTidyDataFile() function.

If the raw data set was downloaded with the downloadRawDataFile() function then no parameter is needed :

generateTidyDataFile()

On the other hand if you downloaded manualy the zip file you need to pass its name to the function, for example :

generateTidyDataFile("rawdata.zip")

The output table is written in the AveragesBySubjectActivity.txt file which can be easily reloaded in R with :

data <- read.table("AveragesBySubjectActivity.txt", header=TRUE)

For more information on the output data set and its variables, see the CodeBook.md file.