Load the dplyr library.

Load the tidyr library.

1.Read the dataset and stored in the data frame format.

features: List of all features.

activity_labels: Links the class labels with their activity name.

X_train: Training set.

y_train: Training labels.

X_test: Test set.

y_test: Test labels.

subject_train: Each row identifies the subject who performed the activity for each window sample. Its range is from 1 to 30.

subject_test: Each row identifies the subject who performed the activity for each window sample. Its range is from 1 to 30.

The data into a suitable for "dplyr" library data frame format.

2.Naming the columns of data.

3.Remove duplicate column.

Transfer X_test to remove duplicate rows, then transpose.(removing the X_test duplicate column)

Transfer X_train to remove duplicate rows, then transpose.

4.Extracts only the measurements on the mean and standard deviation for each measurement.

Select test set column containing “mean()” into X_test_std.

Select test set column containing “std()” into X_test_std.

Combined subject_test, y_test, X_test_mean X_test_std to as test_set according to column.

Delete X_test_mean and X_test_std.

Select train set column containing “mean()” into X_train_std.

Select train set column containing “std()” into X_train_std.

Combined subject_train, y_train, X_train_mean X_train_std to as train_set according to column.

Delete X_train_mean and X_train_std.

Merges the training and the test sets to create one data set.

Merging test_set and train_set to create one data set called data_set in rows.

sort data_set in the order of the subject,the same subject value in the order of activity_labels.

5.Uses descriptive activity names to name the activities in the data set.

Merging data_set and activity_labels in the same column name.(the same column name is activity_labels)

Delete activity_labels columns of data_set.

6.Appropriately labels the data set with descriptive variable names. (tidy the data)

Delete "()" in the data_set column names.

Delete "-mean" in the data_set column names.

Replace "-" to "_" in the data_set column names.

The data_set from tBodyAcc_X to fBodyBodyGyroJerkMag column,the column names as the values of the signals,the values as the values of the mean,duplicating all other columns as needed.

Delete "_std" in the data_set column names.

The data_set from tBodyAcc_X to fBodyBodyGyroJerkMag column,the column names as the values of the signals,the values as the values of the std,duplicating all other columns as needed.

Delete the fifth column of data_set.(remove duplicate the signals)

7.creates a second, independent tidy data set with the average of each variable for each activity and each subject.

Group data_set by the Column of the subject, activities and the signals,the results in data_set_groups.

Each group for the average of the mean and STD, and deposited in the data_set_tidy.

8.The data_set_tidy output to a text file called data_set_tidy.txt.