rbind two datatables and make a new column in R-CodePudding

Hi i have two datasets which represent to different groups:

student_details <- c("John", "Henrick", "Maria", "Lucas", "Ali")
student_class <- c("High School", "College", "Preschool", "High School", "college")
df1 <- data.frame(student_details, student_class)

#another dataframe

Student_details<-c("Bracy","Evin")
Student_class<-c("High school","College")
Student_rank<-c("A","A ")
df2<-data.frame(Student_class,Student_details,Student_rank)

df2

I need to rbind df1 and df2 even though the lenght is unequal and make a third column in the final called "dataset" which indicates which dataset it is from:

CodePudding user response：

I am assuming your column name student_details,student_class is same across data frame. You can use bind_rows which is more flexible than rbind. It will create NA values.

student_details <- c("John", "Henrick", "Maria", "Lucas", "Ali")
student_class <- c("High School", "College", "Preschool", "High School", "college")
df1 <- data.frame(student_details, student_class)


student_details<-c("Bracy","Evin")
student_class<-c("High school","College")
student_rank<-c("A","A ")
df2<-data.frame(student_details,student_class,student_rank)

library(dplyr)

df_full<-bind_rows(df1,df2)

CodePudding user response：

You can use the rbindlist() function from the data.table package to accomplish this.

It is important that the column names are the same in both dataframes, as you want to bind by column name.

#convert uppercase letters in column names to lower case. 
names(df2) <- tolower(names(df2))

Next, bind them together:

library(data.table)
final_df <- rbindlist(list(df1, df2), use.names = T, fill = T, idcol = "dataset")
final_df

Output:

   dataset student_details student_class student_rank
1:       1            John   High School         <NA>
2:       1         Henrick       College         <NA>
3:       1           Maria     Preschool         <NA>
4:       1           Lucas   High School         <NA>
5:       1             Ali       college         <NA>
6:       2           Bracy   High school            A
7:       2            Evin       College           A

CodePudding user response：

With your specific df1 and df2, we can try merge from base R

> merge(df1, df2, all = TRUE, sort = FALSE)
  student_details student_class student_rank
1            John   High School         <NA>
2         Henrick       College         <NA>
3           Maria     Preschool         <NA>
4           Lucas   High School         <NA>
5             Ali       college         <NA>
6           Bracy   High school            A
7            Evin       College           A

but the data.table option using rbindlist should work in general sense (see answer by @Flap)