Adding a new column to each element in a list of tables or data frames

Question

I have a list of files. I also have a list of \"names\" which I substr() from the actual filenames of these files. I would like to add a new column to each of t

Answer 1

The purrr way, using map2

library(dplyr)
library(purrr)

map2(filelist, ID, ~cbind(.x, SampleID = .y))

#[[1]]
#  x y SampleId
#1 1 a       1A
#2 2 b       1A
#3 3 c       1A

#[[2]]
#  x y SampleId
#1 4 d       IB
#2 5 e       IB
#3 6 f       IB

Or can also use

map2(filelist, ID, ~.x %>% mutate(SampleId = .y))

---

If you name the list, we can use imap and add the new column based on it's name.

names(filelist) <- c("1A","IB")
imap(filelist, ~cbind(.x, SampleID = .y))
#OR
#imap(filelist, ~.x %>% mutate(SampleId = .y))

which is similar to using Map

Map(cbind, filelist, SampleID = names(filelist))