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如何用dplyr交换datatable中的TRUE和FALSE

dplyr r

Mark · 技术社区 · 5 年前

我希望在a列中的特定行中将值改为它们的相反值(T变为F,反之亦然) datatable

我知道 x <- !x 为…工作 T/F 变量,但如何完成 dplyr 方法:

library(dplyr)
library(datatable)
library(magrittr)
mtcars$selected <- T
mtcars %>% select(selected) %>% slice(c(1,4,5)) %>% mutate(??)

2 回复 | 直到 5 年前

r2evans 5 年前

如果你只是想子集那么,@Shree的回答可能是对的。如果您只想反转这些行,但保留所有行,则类似于:

在 dplyr :

library(dplyr)
mtcars %>%
  mutate(selected = TRUE) %>%
  # the heart of the answer
  mutate(selected = if_else(row_number() %in% c(1, 4, 5), !selected, selected))
#     mpg cyl  disp  hp drat    wt  qsec vs am gear carb selected
# 1  21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4    FALSE
# 2  21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4     TRUE
# 3  22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1     TRUE
# 4  21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1    FALSE
# 5  18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2    FALSE
# 6  18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1     TRUE
# 7  14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4     TRUE
# 8  24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2     TRUE
# ...

你说过 datatable ,我想你是说 data.table ,在这种情况下

library(data.table)
DT <- as.data.table(mtcars)
DT[, selected := TRUE]
DT[, selected := ifelse(.I %in% c(1, 3, 4), !selected, selected)]
head(DT, n = 8)
#      mpg cyl  disp  hp drat    wt  qsec vs am gear carb selected
#  1: 21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4    FALSE
#  2: 21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4     TRUE
#  3: 22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1    FALSE
#  4: 21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1    FALSE
#  5: 18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2     TRUE
#  6: 18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1     TRUE
#  7: 14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4     TRUE
#  8: 24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2     TRUE

或者像管道一样

library(magrittr)
DT <- as.data.table(mtcars)
DT %>%
  .[, selected := TRUE] %>%
  .[, selected := ifelse(.I %in% c(1, 3, 4), !selected, selected)]
head(DT, n = 8)
#     mpg cyl  disp  hp drat    wt  qsec vs am gear carb selected
# 1: 21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4    FALSE
# 2: 21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4     TRUE
# 3: 22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1    FALSE
# 4: 21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1    FALSE
# 5: 18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2     TRUE
# 6: 18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1     TRUE
# 7: 14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4     TRUE
# 8: 24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2     TRUE

在基R ,您可以这样做:

mtcars$selected <- TRUE
mtcars$selected[c(1, 3, 4)] <- !mtcars$selected[c(1, 3, 4)]
head(mtcars, n = 8)
#                    mpg cyl  disp  hp drat    wt  qsec vs am gear carb selected
# Mazda RX4         21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4    FALSE
# Mazda RX4 Wag     21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4     TRUE
# Datsun 710        22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1    FALSE
# Hornet 4 Drive    21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1    FALSE
# Hornet Sportabout 18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2     TRUE
# Valiant           18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1     TRUE
# Duster 360        14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4     TRUE
# Merc 240D         24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2     TRUE

Shree 5 年前

有一个办法-

mtcars %>% 
  select(selected) %>% 
  slice(c(1,4,5)) %>% 
  mutate(
    selected = !selected # or as.logical(1 - selected)
  )