Getting and Cleaning Data - Course Project

About the Script

The run_analysis.R performs the following procedures:

1. Verifies existence of the Data folder. If such folder does not exist, R will download it. The URL of the data is the following link: https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip

2. The data files (X,Y files of the train and test data sets) are loaded as CSV files.

3. Data frames are merged by using rbindand cbind combining Subject, Activity and Measurements observations.

4. Columns' names are given by extracting them from features.txt file, which is included in the data set.

5. Columns that contain mean or std are found by using grepl.

6. IDs and names of activities are read from the activity_labels.txt file. The factor function is used to convert the activity IDs into descriptive names.

7. Using ddply a second data set is created. This data set includes the average of each variable given each activity and subject.

8. Finally, write.csv is used to create the tidy data set in the same folder as run_analysis.R script.