run_analysis script
The script run_analysis contains a function called tidyDataSamsung. Make sure your working directory is one node above the "UCI HAR Dataset" folder and then, to execute the script, run the following commands in R:
-
source("run_analysis.R") -
data <- tidyDataSamsung()
The script performs the following operations:
- From the file "features.txt", it extracts all the variables names. By means of the "grep" function, it extract all those that contain "mean" or "std" in their names.
- It reads the file "activity_labels.txt" containing the activity names and the labels associated with them.
- Using the information from point 1, it reads the files "X_train.txt" and "X_test.txt", extracting only the columns corresponding to the variables we need. It also assigns the variables names to each column.
- It reads the files "y_train.txt" and "y_test.txt" containing the labels of the activities performed by each subject.
- It reads the files "subject_train.txt" and "subject_test.txt" indicating the subject each observation is associated with.
- It creates two data frames, data_train and data_test, by merging all the observations with the table of activities and activity labels.
- It merges the data_train and data_test sets, in a data frame containing, for each observation, the subject, the activity performed, and all the variables.
- It renames the variables by dropping the parentheses.
- Finally, it creates a data frame with the mean of each variable for each subject and activity.