rbind 两个数据表并在 R 中创建一个新列

Question

嗨，我有两个代表不同组的数据集：

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)

#另一个 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

我需要 rbind df1 和 df2 即使长度不相等，并在最后一个名为“数据集”的第三列中指示它来自哪个数据集：

Answer 1

您可以使用 data.table package 中的data.table rbindlist() function 来完成此操作。

两个数据框中的列名相同很重要，因为您要按列名绑定。

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

接下来，将它们绑定在一起：

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+

Answer 2

我假设您的列名 student_details,student_class 在数据框中是相同的。 您可以使用比 rbind 更灵活的 bind_rows。 它将创建 NA 值。

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)

Answer 3

使用您的特定df1和df2 ，我们可以尝试从基础 R merge

> 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+

但是使用rbindlist的data.table选项应该在一般意义上起作用（参见@Flap的回答）