Rename only if field exists, otherwise ignore

Question

One can rename a field:

mtcars %>% rename(bla = mpg)

But if the field doesn't exist, an error:

    mtcars %>% rename(MPG = mpg, CYL = cyl, bla = uyhgfrtgf)
Error: Can't rename columns that don't exist.
x Column `uyhgfrtgf` doesn't exist

I looked at ?rename_if and it says this is now superseded by rename_with().

What's the 'right' way to attempt to rename fields but with a possibility they don't exist (e.g. in this case a ShinyApp with filter selectors).

Also see [Avoiding error when using rename in dplyr and column doesn't exist](https://stackoverflow.com/q/34275576/1082435) — wibeasley, May 17 '23 at 23:41

Ritchie Sacramento · Accepted Answer · 2022-03-02T12:10:32.217

71

Use any_of() with a named vector. any_of() doesn't error if a variable isn't found.

library(dplyr)

lookup <- c(MPG = "mpg", CYL = "cyl", bla = "uyhgfrtgf")

mtcars %>%
   rename(any_of(lookup))

                   MPG CYL disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
...

edited Mar 02 '22 at 12:10

answered Aug 28 '21 at 21:11

Ritchie Sacramento

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Are you aware of an base R approach as well? If so, could you please refer to? – Pax Jul 21 '23 at 10:09

score 11 · Answer 2 · answered Aug 28 '21 at 16:02

11

I'm pretty sure you can do this with NSE but I can't handle this (yet?).

So you could define a lookup variable first:

lookup <- c("mpg" = "MPG", "cyl" = "CYL", "uyhgfrtgf" = "bla")

Attention: it's the other way round as in your rename function.

Now you could use

library(dplyr)

df %>% 
  rename_with(.fn = ~lookup[.x], .cols = intersect(names(.), names(lookup)))

which returns

                     MPG CYL  disp  hp drat    wt  qsec vs am gear carb
Mazda RX4           21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
Datsun 710          22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
Valiant             18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
Duster 360          14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
Merc 240D           24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2

answered Aug 28 '21 at 16:02

Martin Gal

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2

Thanks for this, what's "NSE"? Non standard evaluation? – Doug Fir Aug 28 '21 at 16:30
Yes. Non standard evaluation. Using some curly-curly or big-bang-operators or something like that I don't understand. – Martin Gal Aug 28 '21 at 16:33
Ah I see. Yeah dito, I've found it more tricky to truly grasp NSE in an intuitive way – Doug Fir Aug 28 '21 at 16:34
1

@DougFir NSE is one of my favorite topics in R you can start from here if you wanna learn more : https://tidyeval.tidyverse.org/index.html – Anoushiravan R Aug 28 '21 at 16:51
I had to switch my accepted answer here, the new one just reads more intuitively to me. Thanks all the same for your answer! – Doug Fir Aug 29 '21 at 12:10
1

It's okay. 27 Phi 9's answer is great. – Martin Gal Aug 29 '21 at 13:02

akrun · Answer 3 · 2021-08-28T19:03:38.727

We may use

library(dplyr)
lookup <-c("MPG" = "mpg", "CYL" = "cyl", "bla" = "uyhgfrtgf")
mtcars %>% 
    rename(!!! lookup[names(.) %in% lookup])
                     MPG CYL  disp  hp drat    wt  qsec vs am gear carb
Mazda RX4           21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
Datsun 710          22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
Valiant             18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
Duster 360          14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
Merc 240D           24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
Merc 230            22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
Merc 280            19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
...

score 7 · Answer 4 · answered Aug 28 '21 at 21:04

We could use rename_with from dplyr package and wrap it in a ~case_when function:

library(dplyr)

mtcars %>% 
    rename_with(
        ~ case_when(
        . == "mpg" ~ "MPG",
        . == "cyl" ~ "CYL",
        . == "bla" ~ "uyhgfrtgf",
        TRUE ~ .))


                     MPG CYL  disp  hp drat    wt  qsec vs am gear carb
Mazda RX4           21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
Datsun 710          22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2

score 3 · Answer 5 · answered Aug 28 '21 at 15:58

3

You could use the following solution:

library(dplyr)
library(stringr)

names <- c("mpg", "cyl", "sdad")
reps <- c("MPG", "CYL", "BLA")

mtcars %>%
  rename_with(~ str_replace_all(.x, "\\w+", reps[names(mtcars) %in% names]), matches(names))

                   MPG CYL disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

answered Aug 28 '21 at 15:58

Anoushiravan R

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Nice one! But one hint: you shouldn't name your vector `names` since this is the name of an actual function. – Martin Gal Aug 28 '21 at 16:17
1

Yes indeed! however they live in two different environments, mine in global and the other in base so they won't affect one another. But yes you are right. – Anoushiravan R Aug 28 '21 at 16:20
1

This is truely right, but some strange structures like `names(names) <- names(reps)` could occure which are... a bit confusing. ;-) – Martin Gal Aug 28 '21 at 16:22
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Yes it's totally not recommended and I was trying so hard to deliver and answer fast :D – Anoushiravan R Aug 28 '21 at 16:33
1

You did answer first! :-) – Martin Gal Aug 28 '21 at 16:35
No it's not important at all. Your answer is great. – Anoushiravan R Aug 28 '21 at 16:38

Rename only if field exists, otherwise ignore

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