Dataframe name to column in list of dataframes using purrr-CodePudding

I have a list of data frames that are imported from excel files. Each file is imported and named after the batch they represent.

Below is an example:

library(tidyverse)
batch_1 <- data.frame(A = 1:3,
                      B = 4:6)
batch_2 <- data.frame(A = 1:3,
                      B = 4:6)
batch_3 <- data.frame(A = 1:3,
                      B = 4:6)
my_list <- list(batch_1, batch_2, batch_3)

I now want to create a new column in each of the data frames that is the name of each data frame.

So it will for each data frame look something like:

  A B   batch
1 1 4 batch_1
2 2 5 batch_1
3 3 6 batch_1

which I will then combine to one data frame in order to plot. I can do it manually by mutate(batch = deparse(substitute(batch_1))) but I'm struggeling with "purrr-ifying" this.

map(my_list, ~mutate(batch = deparse(substitute(.x))))

gives an error: Error in UseMethod("mutate") : no applicable method for 'mutate' applied to an object of class "character"

It does not have to be purrr specific, any method is welcomed.

EDIT: @user63230 solution works. But, as is typical, you find a solution when you already have one!

An alternative solution for this case is found in the later combination of data frames into one.

bind_rows(my_list, .id = "batch") will added, an id column with the name of the data frame.

CodePudding user response：

Another way is to use lst instead of list which automatically names the list for you with imap which uses these names directly (.y).

library(tidyverse)
my_list <- lst(batch_1, batch_2, batch_3)
purrr::imap(my_list, ~mutate(.x, batch = .y))

# $batch_1
#   A B   batch
# 1 1 4 batch_1
# 2 2 5 batch_1
# 3 3 6 batch_1

# $batch_2
#   A B   batch
# 1 1 4 batch_2
# 2 2 5 batch_2
# 3 3 6 batch_2

# $batch_3
#   A B   batch
# 1 1 4 batch_3
# 2 2 5 batch_3
# 3 3 6 batch_3

CodePudding user response：

Alternate answer using base and plyr would be,

#import all batch dataframes 
df= mget(grep(pattern = "bat", x = ls(), value = TRUE))

#convert the list to dataframe
df = ldply(df, as.data.frame)