join data frames in two separate lists R

Question

I have a 2 lists of 6 data frames each.

listofdf_1 <- list(a, b, c, d, e, f)
listofdf_2 <- list(a2, b2, c2, d2, e2, f2)

I want to inner_join data frame a with a2, b with b2, c with c2 etc. The join column is : ID1

I've written a function :

merge_on_id <- function(x, y, join_field) {
  require(dplyr)
  inner_join(x, y, by = join_field)
}

Now I'm joining one by one: merge_on_id(listofdf_1[[1]], listofdf_2[[1]], by = "ID1") etc.

I'm wondering if there is a way to join all six in a single line instead of having to repeat for each element of the list.

akrun · Accepted Answer · 2015-11-03 17:00:20Z

1

If we need to inner_join corresponding elements of lists, we can use Map.

 Map(inner_join, listofdf_1, listofdf_2, MoreArgs=list(by='ID1'))

data

listofdf_1 <- list(a= data.frame(ID1= LETTERS[1:3], Value= 1:3, stringsAsFactors=FALSE),
          b = data.frame(ID1= LETTERS[4:7], V1= 4:7, stringsAsFactors=FALSE))

listofdf_2 <- list(a2= data.frame(ID1= LETTERS[1:5], Value= 6:10, stringsAsFactors=FALSE), 
      b2 = data.frame(ID1= LETTERS[4:9], V1= 4:9, stringsAsFactors=FALSE))

edited Nov 3, 2015 at 17:00

answered Nov 3, 2015 at 16:47

akrun

891k38 gold badges590 silver badges700 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

vagabond Over a year ago

thanks! the inner join in MAP, is it from dplyr or is it base?

akrun Over a year ago

@vagabond It's a base R option, but we could do this with dplyr, possibly in a couple of steps (I thought you wanted a single step answer).

akrun Over a year ago

@vagabond It depends upon the number of steps. Also, you can check the speed using system.time or microbenchmark.

Collectives™ on Stack Overflow

join data frames in two separate lists R

1 Answer 1

data

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

data

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related