I need to pass a string as a column name using dplyr (code below). I can't get it to work. I've tried using [[name]] and .data[[name]] and this doesn't work. I need a solution specifically that allows me to rename a column as the string I've specified in the variable name.
colnames(mtcars) -> cols
rename_cols <- function(col) {
name = paste0(col, "_new") #I want to be able to parse this into the rename function below
mtcars %>%
rename(
name = col,
)
}
lapply(cols, rename_cols)
CodePudding user response：
I would use a named vector instead of trying to mess around with the dplyr programming nuances. A benefit is that this method is already vectorized.
rename_cols <- function(col) {
name = paste0(col, "_new") #I want to be able to parse this into the rename function below
mtcars %>%
rename(setNames(col, name))
}
rename_cols(colnames(mtcars))
# mpg_new cyl_new disp_new hp_new drat_new wt_new qsec_new vs_new am_new gear_new carb_new
# 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
# ...
Edit
In this case, you might also find rename_with() to be what you need.
library(dplyr)
colnames(mtcars) -> cols
mtcars %>%
rename_with(~ paste0(., "_new"), any_of(cols))
# which is the same as the more concise but maybe less clear...
mtcars %>%
rename_with(paste0, any_of(cols), "_new")
CodePudding user response：
Another option using some glue magic and the := assignment operator:
library(dplyr)
colnames(mtcars) -> cols
rename_cols <- function(col) {
name = paste0(col, "_new") #I want to be able to parse this into the rename function below
mtcars %>%
rename(
"{name}" := col,
)
}
lapply(cols, rename_cols)[1:2]
#> Note: Using an external vector in selections is ambiguous.
#> ℹ Use `all_of(col)` instead of `col` to silence this message.
#> ℹ See <https://tidyselect.r-lib.org/reference/faq-external-vector.html>.
#> This message is displayed once per session.
#> [[1]]
#> mpg_new 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
#> Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4
#> Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3
#> Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3
#> Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3
#> Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4
#> Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4
#> Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4
#> Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1
#> Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2
#> Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1
#> Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1
#> Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2
#> AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2
#> Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4
#> Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2
#> Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1
#> Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2
#> Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2
#> Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4
#> Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6
#> Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8
#> Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2
#>
#> [[2]]
#> mpg cyl_new 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
#> Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4
#> Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3
#> Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3
#> Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3
#> Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4
#> Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4
#> Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4
#> Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1
#> Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2
#> Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1
#> Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1
#> Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2
#> AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2
#> Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4
#> Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2
#> Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1
#> Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2
#> Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2
#> Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4
#> Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6
#> Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8
#> Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2
CodePudding user response：
This seems like doing things the hard way: you can replace the whole code with:
mtcars %>% setNames(paste0(cols, "_new"))
Or, if you only want to rename some columns:
names(mtcars[cols]) <- paste0(names(mtcars[cols]), "_new")
If for some reason this isn't what you want, you can turn name into a symbol and use !!name :=
colnames(mtcars) -> cols
rename_cols <- function(col) {
name = paste0(col, "_new")
name <- rlang::ensym(name)
mtcars[col] %>%
rename(
!!name := all_of(col),
)
}
as.data.frame(lapply(cols, rename_cols))
#> mpg_new cyl_new disp_new hp_new drat_new wt_new qsec_new
#> Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46
#> Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02
#> Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61
#> Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44
#> Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02
#> Valiant 18.1 6 225.0 105 2.76 3.460 20.22
#> Duster 360 14.3 8 360.0 245 3.21 3.570 15.84
#> Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00
#> Merc 230 22.8 4 140.8 95 3.92 3.150 22.90
#> Merc 280 19.2 6 167.6 123 3.92 3.440 18.30
#> Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90
#> Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40
#> Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60
#> Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00
#> Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98
#> Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82
#> Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42
#> Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47
#> Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52
#> Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90
#> Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01
#> Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87
#> AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30
#> Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41
#> Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05
#> Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90
#> Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70
#> Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90
#> Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50
#> Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50
#> Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60
#> Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60
#> vs_new am_new gear_new carb_new
#> Mazda RX4 0 1 4 4
#> Mazda RX4 Wag 0 1 4 4
#> Datsun 710 1 1 4 1
#> Hornet 4 Drive 1 0 3 1
#> Hornet Sportabout 0 0 3 2
#> Valiant 1 0 3 1
#> Duster 360 0 0 3 4
#> Merc 240D 1 0 4 2
#> Merc 230 1 0 4 2
#> Merc 280 1 0 4 4
#> Merc 280C 1 0 4 4
#> Merc 450SE 0 0 3 3
#> Merc 450SL 0 0 3 3
#> Merc 450SLC 0 0 3 3
#> Cadillac Fleetwood 0 0 3 4
#> Lincoln Continental 0 0 3 4
#> Chrysler Imperial 0 0 3 4
#> Fiat 128 1 1 4 1
#> Honda Civic 1 1 4 2
#> Toyota Corolla 1 1 4 1
#> Toyota Corona 1 0 3 1
#> Dodge Challenger 0 0 3 2
#> AMC Javelin 0 0 3 2
#> Camaro Z28 0 0 3 4
#> Pontiac Firebird 0 0 3 2
#> Fiat X1-9 1 1 4 1
#> Porsche 914-2 0 1 5 2
#> Lotus Europa 1 1 5 2
#> Ford Pantera L 0 1 5 4
#> Ferrari Dino 0 1 5 6
#> Maserati Bora 0 1 5 8
#> Volvo 142E 1 1 4 2
Created on 2022-03-08 by the reprex package (v2.0.1)