R- Referencing different dataframes in a loop

Question

I am brand new to R so if I\'m thinking about this completely wrong feel free to tell me. I have a series of imported dataframes on power plants, one of each year (Plant1987, Pl

Answer 1

Here are some codes to give you some ideas. I used the mtcars data frame as an example to create a list with three data frames. After that I used two solutions to add the year (2000 to 2002) to each data frame. You will need to modify the codes for your data.

# Load the mtcars data frame
data(mtcars)

# Create a list with three data frames
ex_list <- list(mtcars, mtcars, mtcars)

# Create a list with three years: 2000 to 2002
year_list <- 2000:2002

Solution 1: Use lapply from base R

ex_list2 <- lapply(1:3, function(i) {

  dt <- ex_list[[i]]

  dt[["Year"]] <- year_list[[i]]

  return(dt)
})

Solution 2: Use map2 from purrr

library(purrr)    

ex_list3 <- map2(ex_list, year_list, .f = function(dt, year){

  dt$Year <- year

  return(dt)
})

ex_list2 and ex_list3 are the final output.