Getting and Cleaning Data Assignment

Assignment for MOOC: Getting and Cleaning Data

This program requires a zip file with Samsung data to work. This data can be downloaded here.

This program does three things. It includes a function for each, plus a run() function to execute the script.

With more time, I would have created a separate script to execute the unzipping and extracting of data. I would also have properly commented the files and spent more time thinking about what to call the variables. I expect that, with a file of this size, there is

But anyway - the functions:

getAllFiles

Simple method to unzip file, and return a file.path to a temporary directory, where all the data is.

getLabels

Taking the local filepath to the temporary directory, this method gets the label data: label names for activities (a), index of columns to keep (vix) - only mean and standard deviation variables and column names for those variables (vlb). This is returned in a list with keys a, vix and vlb.

open_and_mergeTXT

Taking the variable data from the above function, this one finds the data from the test/train folders and merges the subject, activity and features data. It returns a data.frame

getColM

Uses the colMeans function to calculate column means

getAverages

Gets a data.frame of all the possible values of activity and subject and calls the above method. Then uses a do.call of rbind to convert the list from an lapply to put it all together

run

Runs all of the above code