Suppose that we have three dataframes dfa

dfb

dfc

how could I rename the dfa id column from 1,2 to b,a using R?

Please help me solve this question! Thank you so much!

CodePudding user response：

One dplyr approach would be to use recode like so:

library(dplyr)

dfa |> 
  mutate(id = recode(id, !!!setNames(dfc$primary, dfc$colname)))
#>   name id
#> 1 jack  b
#> 2 rose  a

or a second option would be to use a left_join:

dfa |> 
  left_join(dfc, by = c("id" = "colname")) |> 
  select(name, id = primary)
#>   name id
#> 1 jack  b
#> 2 rose  a

DATA

dfa <- data.frame(
              name = c("jack", "rose"),
                id = c(1L, 2L)
)

dfc <- data.frame(
           primary = c("a", "b"),
           colname = c(2L, 1L)
)

CodePudding user response：

I haven't understood if the relationship between all three datasets is like this: dfa$id is equal to dfc$colname, and dfc$primary is equal to dfb$id, but if so, here's a possible answer:

# Load the dataframes
dfa <- data.frame(name = c("jack", "rose"),
                  id = c(1, 2))
dfb <- data.frame(id = c("a", "b"),
                  job = c("student", "tutor"))
dfc <- data.frame(primary = c("a", "b"),
                  colname = c(2, 1))

# Obtain the indexes that match between dfa and dfc
index <- match(dfa$id, dfc$colname)

# Set the id from dfa as the id in dfb taking into account the previous indices
dfa$id <- dfb$id[index]

# Print results
dfa

  name id
1 jack  b
2 rose  a