codebook.rmd

---
title: "codebook"
author: "dawky"
date: "Friday, December 08, 2017"
output: word_document
---

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```{r}
setwd("D:/r/coursera/gettingcleandata")
library(dplyr)

#1
#combine the data,read the x_train,y_train data,subject_train data and combine them into train data, do the same work for the test data, and then put the data together
trainx <- read.table("./UCI HAR Dataset/train/X_train.txt")
trainy <- read.table("./UCI HAR Dataset/train/y_train.txt")
trainsubject <- read.table("./UCI HAR Dataset/train/subject_train.txt")
testx <- read.table("./UCI HAR Dataset/test/X_test.txt")
testy <- read.table("./UCI HAR Dataset/test/y_test.txt")
testsubject <- read.table("./UCI HAR Dataset/test/subject_test.txt")

train <- cbind(trainsubject, trainy, trainx)
test <- cbind(testsubject, testy, testx)
dat <- rbind(train, test)

#2
#find the mean and std, from the feature_info file, we know the "mean" and ¡°std" word appear in the variable name
#I firstly select the needed variable from the features.txt file, and find the position of these variables from the featurename(feature2), and then apply it to the original data
feature<- read.table("./UCI HAR Dataset/features.txt")
feature2 <- grep(("mean\\(\\)|std\\(\\)"), feature[, 2])
featurename<-feature[feature2,2]
dat2 <- dat[, c(1, 2, feature2+2)] 
colnames(dat2)<-c("subject","activity",paste(featurename))

#3
#change the activity number with name,view the activity name, find the number of each activity, and replace them
activity<- read.table("./UCI HAR Dataset/activity_labels.txt")
View(activity)
dat2[,2][dat2[,2]== 1] <- "Walking"
dat2[,2][dat2[,2] == 2] <- "Walking Upstairs"
dat2[,2][dat2[,2] == 3] <- "Walking Downstairs"
dat2[,2][dat2[,2] == 4] <- "Sitting"
dat2[,2][dat2[,2] == 5] <- "Standing"
dat2[,2][dat2[,2] == 6] <- "Laying"

#4
#redo the step2, change the short word into their full name, rewrite the featurename, and apply it to the colname 
#for example, from the feature_info.txt file, we know that Acc represent for Accelerator, Mag represent for Magnitude,and it's them same for "Gyro"and "Gyroscope","t"and "time","f"and "frequency"
#we change our featurename list, screen for the original word and replace it with full name, and apply it to the colname
featurename2<-featurename
featurename2<-gsub("Acc", "Accelerator", featurename2)
featurename2<-gsub("Mag", "Magnitude", featurename2)
featurename2<-gsub("Gyro", "Gyroscope", featurename2)
featurename2<-gsub("^t", "time", featurename2)
featurename2<-gsub("^f", "frequency", featurename2)

colnames(dat2)<-c("subject","activity",paste(featurename2))


#5
#aggregate each col by the two listed variable using group_by, and then export it to clean txt file

cleandata<-dat2%>%group_by(subject,activity)%>%summarise_each(funs(mean))

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

##summary and decription for the variables in the cleandata
##variable for the feature
# "timeBodyAccelerator-mean()-X"                     "timeBodyAccelerator-mean()-Y"                    
# "timeBodyAccelerator-mean()-Z"                     "timeBodyAccelerator-std()-X"                     
# "timeBodyAccelerator-std()-Y"                      "timeBodyAccelerator-std()-Z"                     
# "timeGravityAccelerator-mean()-X"                  "timeGravityAccelerator-mean()-Y"                 
# "timeGravityAccelerator-mean()-Z"                  "timeGravityAccelerator-std()-X"                  
# "timeGravityAccelerator-std()-Y"                   "timeGravityAccelerator-std()-Z"                  
# "timeBodyAcceleratorJerk-mean()-X"                 "timeBodyAcceleratorJerk-mean()-Y"                
# "timeBodyAcceleratorJerk-mean()-Z"                 "timeBodyAcceleratorJerk-std()-X"                 
# "timeBodyAcceleratorJerk-std()-Y"                  "timeBodyAcceleratorJerk-std()-Z"                 
# "timeBodyGyroscope-mean()-X"                       "timeBodyGyroscope-mean()-Y"                      
# "timeBodyGyroscope-mean()-Z"                       "timeBodyGyroscope-std()-X"                       
# "timeBodyGyroscope-std()-Y"                        "timeBodyGyroscope-std()-Z"                       
# "timeBodyGyroscopeJerk-mean()-X"                   "timeBodyGyroscopeJerk-mean()-Y"                  
# "timeBodyGyroscopeJerk-mean()-Z"                   "timeBodyGyroscopeJerk-std()-X"                   
# "timeBodyGyroscopeJerk-std()-Y"                    "timeBodyGyroscopeJerk-std()-Z"                   
# "timeBodyAcceleratorMagnitude-mean()"              "timeBodyAcceleratorMagnitude-std()"              
# "timeGravityAcceleratorMagnitude-mean()"           "timeGravityAcceleratorMagnitude-std()"           
# "timeBodyAcceleratorJerkMagnitude-mean()"          "timeBodyAcceleratorJerkMagnitude-std()"          
# "timeBodyGyroscopeMagnitude-mean()"                "timeBodyGyroscopeMagnitude-std()"                
# "timeBodyGyroscopeJerkMagnitude-mean()"            "timeBodyGyroscopeJerkMagnitude-std()"            
# "frequencyBodyAccelerator-mean()-X"                "frequencyBodyAccelerator-mean()-Y"               
# "frequencyBodyAccelerator-mean()-Z"                "frequencyBodyAccelerator-std()-X"                
# "frequencyBodyAccelerator-std()-Y"                 "frequencyBodyAccelerator-std()-Z"                
# "frequencyBodyAcceleratorJerk-mean()-X"            "frequencyBodyAcceleratorJerk-mean()-Y"           
# "frequencyBodyAcceleratorJerk-mean()-Z"            "frequencyBodyAcceleratorJerk-std()-X"            
# "frequencyBodyAcceleratorJerk-std()-Y"             "frequencyBodyAcceleratorJerk-std()-Z"            
# "frequencyBodyGyroscope-mean()-X"                  "frequencyBodyGyroscope-mean()-Y"                 
# "frequencyBodyGyroscope-mean()-Z"                  "frequencyBodyGyroscope-std()-X"                  
# "frequencyBodyGyroscope-std()-Y"                   "frequencyBodyGyroscope-std()-Z"                  
# "frequencyBodyAcceleratorMagnitude-mean()"         "frequencyBodyAcceleratorMagnitude-std()"         
# "frequencyBodyBodyAcceleratorJerkMagnitude-mean()" "frequencyBodyBodyAcceleratorJerkMagnitude-std()" 
# "frequencyBodyBodyGyroscopeMagnitude-mean()"       "frequencyBodyBodyGyroscopeMagnitude-std()"       
# "frequencyBodyBodyGyroscopeJerkMagnitude-mean()"   "frequencyBodyBodyGyroscopeJerkMagnitude-std()"  

##subject:
#The participant ("subject") ID

##acticity:
#The label of the activity performed when the corresponding measurements were taken
#WALKING (1)
#WALKING_UPSTAIRS (2)
#WALKING_DOWNSTAIRS (3)
#SITTING (4)
#STANDING (5)
#LAYING (6)

```

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