hepatitis <- read.csv("C:/Users/dailo/Downloads/hepatitis.csv")
head(hepatitis)
##   Gender YearBirth YearTrans RouteTrans IV Tx Coc Tatt HBV HIV EtOH Obes Rx Tox
## 1      0      1905      1970        Coc  0  0   1    0   0   0    0    0  0   0
## 2      1      1958      1992        Coc  0  0   1    0   0   0    0    0  0   0
## 3      1      1957      1977        Coc  0  0   1    0   0   0    0    0  0   0
## 4      0      1945      1968        Coc  0  0   1    1   0   0    1    0  0   0
## 5      1      1956      1979        Coc  0  0   1    0   0   0    0    0  0   0
## 6      0      1939      1973         IV  1  0   0    0   0   0    1    0  0   0
##   CLD LFT YWOD Age Bx
## 1   0   1   65  97  I
## 2   0   0   34  44  I
## 3   0   0   20  45 II
## 4   0   0   23  57 II
## 5   0   1   23  46  I
## 6   0   1   34  63 II
hepatitis[,20]=hepatitis[,18]-hepatitis[,17]
colnames(hepatitis)[20]= "YWD"
head(hepatitis[1:3,])
##   Gender YearBirth YearTrans RouteTrans IV Tx Coc Tatt HBV HIV EtOH Obes Rx Tox
## 1      0      1905      1970        Coc  0  0   1    0   0   0    0    0  0   0
## 2      1      1958      1992        Coc  0  0   1    0   0   0    0    0  0   0
## 3      1      1957      1977        Coc  0  0   1    0   0   0    0    0  0   0
##   CLD LFT YWOD Age Bx YWD
## 1   0   1   65  97  I  32
## 2   0   0   34  44  I  10
## 3   0   0   20  45 II  25
hh=hepatitis[,c(-2:-4,-17)]
hh[1:3,]
##   Gender IV Tx Coc Tatt HBV HIV EtOH Obes Rx Tox CLD LFT Age Bx YWD
## 1      0  0  0   1    0   0   0    0    0  0   0   0   1  97  I  32
## 2      1  0  0   1    0   0   0    0    0  0   0   0   0  44  I  10
## 3      1  0  0   1    0   0   0    0    0  0   0   0   0  45 II  25
for (j in 1:13) {
  hh[,j]=factor(hh[,j])
}

hh[1:3,]
##   Gender IV Tx Coc Tatt HBV HIV EtOH Obes Rx Tox CLD LFT Age Bx YWD
## 1      0  0  0   1    0   0   0    0    0  0   0   0   1  97  I  32
## 2      1  0  0   1    0   0   0    0    0  0   0   0   0  44  I  10
## 3      1  0  0   1    0   0   0    0    0  0   0   0   0  45 II  25
levels(hh[,6])
## [1] "0" "1"
levels(hh[,8])
## [1] "0" "1"
levels(hh[,13])
## [1] "0" "1"
library(rpart)

# Build decision tree
heptree <- rpart(Bx ~ ., data = hh)
# Display decision tree
plot(heptree)
text(heptree)