使用 dplyr 对除某些列之外的所有列进行变异

Question

我发现这across()对于在多个列上重复操作非常有用。但是，我仍然没有完全理解如何选择特定列进行操作。

假设我想将函数应用于mtcars、和之外 的所有列。gearcarb

我尝试过类似的东西

# Function to use over columns
demean <- function(x) {
  x - mean(x, na.rm = TRUE)
}

# Use function on all but columns gear and carb
mtcars %>% mutate(across(.cols = select(.,-gear,-carb), demean))

但是，这会引发错误

Error: Problem with `mutate()` input `..1`.
x Must subset columns with a valid subscript vector.
x Subscript has the wrong type `data.frame<

取消选择某些列的正确方法是什么across？

Answer 1

这比你想象的要容易：

mtcars %>% mutate(across(-c(gear, carb), demean))
                        mpg     cyl        disp       hp       drat       wt
Mazda RX4          0.909375 -0.1875  -70.721875 -36.6875  0.3034375 -0.59725
Mazda RX4 Wag      0.909375 -0.1875  -70.721875 -36.6875  0.3034375 -0.34225
Datsun 710         2.709375 -2.1875 -122.721875 -53.6875  0.2534375 -0.89725
Hornet 4 Drive     1.309375 -0.1875   27.278125 -36.6875 -0.5165625 -0.00225
Hornet Sportabout -1.390625  1.8125  129.278125  28.3125 -0.4465625  0.22275
Valiant           -1.990625 -0.1875   -5.721875 -41.6875 -0.8365625  0.24275
Duster 360        -5.790625  1.8125  129.278125  98.3125 -0.3865625  0.35275
Merc 240D          4.309375 -2.1875  -84.021875 -84.6875  0.0934375 -0.02725
Merc 230           2.709375 -2.1875  -89.921875 -51.6875  0.3234375 -0.06725
                      qsec      vs       am gear carb
Mazda RX4         -1.38875 -0.4375  0.59375    4    4
Mazda RX4 Wag     -0.82875 -0.4375  0.59375    4    4
Datsun 710         0.76125  0.5625  0.59375    4    1
Hornet 4 Drive     1.59125  0.5625 -0.40625    3    1
Hornet Sportabout -0.82875 -0.4375 -0.40625    3    2
Valiant            2.37125  0.5625 -0.40625    3    1
Duster 360        -2.00875 -0.4375 -0.40625    3    4
Merc 240D          2.15125  0.5625 -0.40625    4    2
Merc 230           5.05125  0.5625 -0.40625    4    2
 [ reached 'max' / getOption("max.print") -- omitted 23 rows ]