在R中获取具有相同或不同逻辑值的行

Question

我有一个包含两列 T 和 F 的数据框。 我想知道

1. 第一行是T，第二行是F
2. 第一行是F，第二行是T
3. 哪一行都是F

我对这件事几乎没有什么线索，有人能指点一下吗？

Answer 1

你可以使用case when

library(dplyr)
df = data.frame(x = c("T","T","F","F","F"), y = c("T","F","T","F","X"))

df %>%
  mutate(condition = case_when(
    x == "T" & y == "T" ~ "Both are T",
    x == "T" & y == "F" ~ "First is T fecond is F",
    x == "F" & y == "F" ~ "Both are F",
    x == "F" & y == "T" ~ "First is F, second is T",
    TRUE ~ "Something else"
  ))
#>   x y               condition
#> 1 T T              Both are T
#> 2 T F  First is T fecond is F
#> 3 F T First is F, second is T
#> 4 F F              Both are F
#> 5 F X          Something else

^{由reprex package (v2.0.0) 于 2021-08-05 创建}

Answer 2

这是解决问题的一种可能方法：

library(dplyr)

df <- data.frame(a = rep(c(T, F, T, F), each=2),
                 b = rep(c(T, T, F, F), each=2))

#       a     b
# 1  TRUE  TRUE
# 2  TRUE  TRUE
# 3 FALSE  TRUE
# 4 FALSE  TRUE
# 5  TRUE FALSE
# 6  TRUE FALSE
# 7 FALSE FALSE
# 8 FALSE FALSE

df %>% 
  mutate(newcol = case_when(a & !b ~ "first=T second=F",
                            !a & b ~ "first=F second=T",
                            !a & !b ~ "both=F",
                            TRUE ~ "other"))

#       a     b           newcol
# 1  TRUE  TRUE            other
# 2  TRUE  TRUE            other
# 3 FALSE  TRUE first=F second=T
# 4 FALSE  TRUE first=F second=T
# 5  TRUE FALSE first=T second=F
# 6  TRUE FALSE first=T second=F
# 7 FALSE FALSE           both=F
# 8 FALSE FALSE           both=F

Answer 3

您可以将 [a,b] 列视为 2 位二进制数向量，并将 a*2+b 将其从二进制转换为十进制。因此，2*a+b+1 映射到 1,2,3,4。

试试下面的基本 R 代码

transform(
  df,
  newcol = c("both=F", "first=F,second=T", "first=T,second=F", "other")[a * 2 + b + 1]
)

给了

      a     b           newcol
1  TRUE  TRUE            other
2  TRUE  TRUE            other
3 FALSE  TRUE first=F,second=T
4 FALSE  TRUE first=F,second=T
5  TRUE FALSE first=T,second=F
6  TRUE FALSE first=T,second=F
7 FALSE FALSE           both=F
8 FALSE FALSE           both=F

数据

df <- data.frame(a = rep(c(T, F, T, F), each=2),
                 b = rep(c(T, T, F, F), each=2))