Replace levels of a factor variable

• Various ways of replacing a level in the factor variable

• Let’s create a dataframe with three columns

name<-c("A","B","C","D","A",rep("A",5),rep("B",4),rep("D",6),rep("C",3))
number<-c(1:23)
age<-c(23:45)
df<-data.frame(number,name,age)
head(df)

Check levels order

# check the level order
levels(df$name)

[1] "A" "B" "C" "D"

• Let’s replace level A by Ha

levels(df$name)[1]<-"Ha"
levels(df$name)

[1] "Ha" "B"  "C"  "D" 

• replace C by Cong

# Way 2
levels(df$name)[df$name=="C"]<-"Cong"
levels(df$name)

[1] "Ha"   "B"    "Cong" "D"   

• replace all

levels(df$name)<-c("Ha","Ban","Con","Da")
levels(df$name)

[1] "Ha"  "Ban" "Con" "Da"