Getting and Cleaning Data Course Project

This repository is for the final project of Cousera's Getting and Cleaning Data Course (Course 3 of Data Science Specialization).

Repository Contents:

1. data (directory) - directory where all given data is. (will be created upon program execution).
2. README.md - this readme file.
3. run_analisys.R - scripts to manipulate data and generate tidy data.
4. tidy.txt - tidy data, final output of the assignment.
5. codebook.md - codebook o the tidy data.

Instructions to run:

• On R environment, just execute source("run_analisys.R").
• The script will download and unzip the data (if necessary).
• The script will generate two dataframes: all.data and tidy).
• Dataframe all.data contains the merged data (with mean and std measurements) of train and test.
• Dataframe tidy contains the average of each variable for each activity and each subject.
• Dataframe tidy will be writen to a file called "tidy.txt".

Overview of run_analisys.R

Script part (end of file)

1. Calls download.file.and.unzip
2. Creates all.data by calling create.all.data
3. Creates tidy by calling create.tidy

Function download.file.and.unzip

Function that extracts the given zip file (assignment input). If file does not exists, it will download it.

Function read.activities.labels

Function that returns the dataframe of code-activity_labels.

Function read.features

Function that returns a vector of all features in dataset, including the ones we don't want.

Function read.data

Function that reads train and test data (measurements, activities, subjects) and returns the data frame.

• To return train data frame, call read.data with dataType argument equal to "train".
• To return test data frame, call read.data with dataType argument equal to "test".

Function create.all.data

Function that orchestrates previous functions and returns a merged data frame of both train and test data.

Function create.tidy

Function that transforms the "all.data" dataframe into another dataframe with the average of each variable for each activity and each subject.