Trying to rename some data frame columns using dplyr rename_if
and lists of old and new patterns, some column names end up switched in the output.
head(mtcars)
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
lst <- list(Old=c("mpg", "cyl", "disp", "carb", "wt", "gear"), New=c("Miles per Gallon", "Cylinder", "Displacement", "Carburator", "Weight", "Gear"))
mtcars %>%
rename_if(names(.) %in% lst$Old,
function(x){
lst$New[which(lst$Old %in% x)]}) %>%
head()
Miles per Gallon Cylinder Displacement hp drat Carburator
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440
Valiant 18.1 6 225 105 2.76 3.460
qsec vs am Weight Gear
Mazda RX4 16.46 0 1 4 4
Mazda RX4 Wag 17.02 0 1 4 4
Datsun 710 18.61 1 1 4 1
Hornet 4 Drive 19.44 1 0 3 1
Hornet Sportabout 17.02 0 0 3 2
Valiant 20.22 1 0 3 1
We can see that the wt
and Carburator
columns have been switched.
How to rename columns using rename_if
when the reference name lists are not in the same order as the data frame columns?
EDIT The use of rename_at(lst$Old, ~lst$New)
does not work when the reference lists contain names not present in the particular data frame columns.
For example with:
lst <- list(Old=c("mpg", "cyl", "disp", "carb", "wt", "gear", "xtra"), New=c("Miles per Gallon", "Cylinder", "Displacement", "Carburator", "Weight", "Gear", "ExtraCol"))
(see the xtra
and ExtraCol
names)
Instead of rename_if
, try with rename_at
since you have names of columns that you want to replace.
library(dplyr)
head(mtcars) %>% rename_at(lst$Old, ~lst$New)
However, _at
/ _if
/ _all
variants have been superseded so try with rename_with
.
head(mtcars) %>% rename_with(~lst$New, lst$Old)
# Miles per Gallon Cylinder Displacement hp drat Weight qsec vs am Gear Carburator
#Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
#Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
#Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
#Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
In base R, we can do this using match
:
names(mtcars)[match(lst$Old, names(mtcars))] <- lst$New
In case, there are values in lst
which are not present in names we can first filter them and then use the above method.
inds <- lst$Old %in% names(mtcars)
lst <- lapply(lst, `[`, inds)
Replacing which()
by match()
keeps indexes by order of occurrence and solves the problem
mtcars %>% rename_if(names(.) %in% lst$Old, function(x){lst$New[match(x, lst$Old)]})
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