My question is what I said in the title, and I found Duck's question same as mine (How to create in R new variable for each element in a list of data frames with the name of data frame and its value equal to position of the element).
Within my poor knowledge in R, I can't understand well the code though it really got what I wanted.
I know my code can't run but I though the code should like this :
# create a fake data
df1 <- split(mtcars,mtcars$cyl)
# add a new variable that indicate where the element from in the list with the element name
df2 <- map(df1, mutate(from = names(df1)))
Any help will be highly appreciated!
You can use imap from purrr to include name of the list as new column
purrr::imap(df1, ~dplyr::mutate(.x, from = .y))
#$`4`
# mpg cyl disp hp drat wt qsec vs am gear carb from
#1 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 4
#2 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 4
#3 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 4
#4 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 4
#5 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 4
#6 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 4
#7 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 4
#8 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 4
#9 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 4
#10 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 4
#11 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 4
#$`6`
# mpg cyl disp hp drat wt qsec vs am gear carb from
#1 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 6
#2 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 6
#3 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 6
#....
In base R we can use Map
Map(cbind, df1, from = names(df1))
#Same as
#purrr::map2(df1, names(df1), cbind)
Another base R option:
split(transform(mtcars, from=cyl), mtcars$cyl)
We can use transform with Map in base R
Map(transform, df1, from = names(df1))
