是否有R函数仅选择某些行值组合？

Question

我有一个看起来像这样的数据框架：

my_data <- data.frame( 
   letter = c("x","x","x","x","x","y","y","y","y","z","z","z","z"),
   number = c(1,5,6,7,2,3,4,5,6,1,4,4,4))

我现在希望制作一个新的data_frame，其中只有一定的列组合存在（“ x”可以是1,2“ y”可以是3，而“ z”可以是4），所以它会提供这样的东西：

my_data2 <- data.frame( 
   letter = c("x","x","y","z","z"),
   number = c(1,2,3,4,4))

我可以通过if-else来做到这一点，但是有一种更优雅的方式吗？

Answer 1

my_data <- data.frame( 
  letter = c("x","x","x","x","x","y","y","y","y","z","z","z","z"),
  number = c(1,5,6,7,2,3,4,5,6,1,4,4,4))

library(tidyverse)
my_data %>% filter(letter == "x" & number %in% c(1,2) | 
                   letter == "y" & number == 3 |
                   letter == "z" & number == 4
                   )

  letter number
1      x      1
2      x      2
3      y      3
4      z      4
5      z      4
6      z      4

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