script9.R

#
# script9.R
#
# Performs step 9 in the Code Book.
#
# This script generates a new data frame called "averages", organized
# per activity and per subject, and we write it out in CSV format to
# a file called "averages.csv" in the current working directory.
#

# STEP A

ro_names <- names(reduced_observations)
ro_names <- chartr("-", ".", ro_names)
ro_names <- gsub("[()]", "", ro_names)
ro_names <- gsub(',', '.', ro_names)
names(reduced_observations) <- ro_names

# STEP B

grouped <- group_by(reduced_observations, activity_name, subject_id)
averages <- summarize(grouped, 
                      mean.tBodyAcc.X=mean(tBodyAcc.mean.X),
                      mean.tBodyAcc.Y=mean(tBodyAcc.mean.Y),
                      mean.tBodyAcc.Z=mean(tBodyAcc.mean.Z),
                      mean.tGravityAcc.X=mean(tGravityAcc.mean.X),
                      mean.tGravityAcc.Y=mean(tGravityAcc.mean.Y),
                      mean.tGravityAcc.Z=mean(tGravityAcc.mean.Z),
                      mean.tBodyAccJerk.X=mean(tBodyAccJerk.mean.X),
                      mean.tBodyAccJerk.Y=mean(tBodyAccJerk.mean.Y),
                      mean.tBodyAccJerk.Z=mean(tBodyAccJerk.mean.Z),
                      mean.tBodyGyro.X=mean(tBodyGyro.mean.X),
                      mean.tBodyGyro.Y=mean(tBodyGyro.mean.Y),
                      mean.tBodyGyro.Z=mean(tBodyGyro.mean.Z),
                      mean.tBodyGyroJerk.X=mean(tBodyGyroJerk.mean.X),
                      mean.tBodyGyroJerk.Y=mean(tBodyGyroJerk.mean.Y),
                      mean.tBodyGyroJerk.Z=mean(tBodyGyroJerk.mean.Z),
                      mean.tBodyAccMag=mean(tBodyAccMag.mean),
                      mean.tGravityAccMag=mean(tGravityAccMag.mean),
                      mean.tBodyAccJerkMag=mean(tBodyAccJerkMag.mean),
                      mean.tBodyGyroMag=mean(tBodyGyroMag.mean),
                      mean.tBodyGyroJerkMag=mean(tBodyGyroJerkMag.mean),
                      mean.fBodyAcc.X=mean(fBodyAcc.mean.X),
                      mean.fBodyAcc.Y=mean(fBodyAcc.mean.Y),
                      mean.fBodyAcc.Z=mean(fBodyAcc.mean.Z),
                      mean.fBodyAcc.Freq.X=mean(fBodyAcc.meanFreq.X),
                      mean.fBodyAcc.Freq.Y=mean(fBodyAcc.meanFreq.Y),
                      mean.fBodyAcc.Freq.Z=mean(fBodyAcc.meanFreq.Z),
                      mean.fBodyAccJerk.X=mean(fBodyAccJerk.mean.X),
                      mean.fBodyAccJerk.Y=mean(fBodyAccJerk.mean.Y),
                      mean.fBodyAccJerk.Z=mean(fBodyAccJerk.mean.Z),
                      mean.fBodyAccJerk.Freq.X=mean(fBodyAccJerk.meanFreq.X),
                      mean.fBodyAccJerk.Freq.Y=mean(fBodyAccJerk.meanFreq.Y),
                      mean.fBodyAccJerk.Freq.Z=mean(fBodyAccJerk.meanFreq.Z),
                      mean.fBodyGyro.X=mean(fBodyGyro.mean.X),
                      mean.fBodyGyro.Y=mean(fBodyGyro.mean.Y),
                      mean.fBodyGyro.Z=mean(fBodyGyro.mean.Z),
                      mean.fBodyGyro.Freq.X=mean(fBodyGyro.meanFreq.X),
                      mean.fBodyGyro.Freq.Y=mean(fBodyGyro.meanFreq.Y),
                      mean.fBodyGyro.Freq.Z=mean(fBodyGyro.meanFreq.Z),
                      mean.fBodyAccMag=mean(fBodyAccMag.mean),
                      mean.fBodyAccMag.Freq=mean(fBodyAccMag.meanFreq),
                      mean.fBodyBodyAccJerkMag=mean(fBodyBodyAccJerkMag.mean),
                      mean.fBodyBodyAccJerkMag.Freq=mean(fBodyBodyAccJerkMag.meanFreq),
                      mean.fBodyBodyGyroMag=mean(fBodyBodyGyroMag.mean),
                      mean.fBodyBodyGyroMag.Freq=mean(fBodyBodyGyroMag.meanFreq),
                      mean.fBodyBodyGyroJerkMag=mean(fBodyBodyGyroJerkMag.mean),
                      mean.fBodyBodyGyroJerkMag.Freq=mean(fBodyBodyGyroJerkMag.meanFreq),
                      mean.angletBodyAcc.gravity=mean(angletBodyAccMean.gravity),
                      mean.angletBodyAccJerk.gravity=mean(angletBodyAccJerkMean.gravityMean),
                      mean.angletBodyGyro.gravity=mean(angletBodyGyroMean.gravityMean),
                      mean.angletBodyGyroJerk.gravity=mean(angletBodyGyroJerkMean.gravityMean),
                      mean.angleX.gravity=mean(angleX.gravityMean),
                      mean.angleY.gravity=mean(angleY.gravityMean),
                      mean.angleZ.gravity=mean(angleZ.gravityMean))

# STEP C

write.csv(averages, file="averages.csv", row.names=FALSE)
write.table(averages, file="averages.txt", row.names=FALSE)