如何在dplyr中避免使用省略号…？

huangapple
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英文:

How to avoid ellipsis ... in dplyr?

问题

  1. 我想创建一个接受分组参数的函数。它可以是单个或多个变量。我希望它看起来像这样：
  3. ```R
  4. wanted <- function(data, groups, other_params){
  5.   data %>% group_by( {{groups}} ) %>% count()
  6. }

这只在给定单个组时有效，但在存在多个组时会出错。我知道可以使用省略号 ... 来实现以下功能（但我想要的语法是 groups = something）：

  1. not_wanted <- function(data, ..., other_params){
  2.   data %>% group_by( ... ) %>% count()
  3. }

以下是完整的代码：

  1. library(dplyr)
  2. library(magrittr)
  4. iris$group2 <- rep(1:5, 30)
  6. wanted <- function(data, groups, other_params){
  7.   data %>% group_by( {{groups}} ) %>% count()
  8. }
  10. not_wanted <- function(data, ..., other_params){
  11.   data %>% group_by( ... ) %>% count()
  12. }
  14. # 正常运行
  15. wanted(iris, groups = Species )
  16. not_wanted(iris, Species, group2)
  18. # 无法正常运行
  19. wanted(iris, groups = vars(Species, group2) )
  20. wanted(iris, groups = c(Species, group2) )
  21. wanted(iris, groups = vars("Species", "group2") )
  22. #  Error: Column `vars(Species, group2)` must be length 150 (the number of rows) or one, not 2
  2. <details>
  3. <summary>英文:</summary>
  5. I want to create a function that takes a grouping argument. Which can be a single or multiple variables. I want it to look like this:

wanted <- function(data, groups, other_params){
data %>% group_by( {{groups}} ) %>% count()
}

  2. This work only when a single group is given but breaks when there are multiple groups. I know it&#39;s possible to use the following with ellipsis `...` (But I want the syntax `groups = something`):

not_wanted <- function(data, ..., other_params){
data %>% group_by( ... ) %>% count()
}

  2. Here is the entire code:

library(dplyr)
library(magrittr)

iris$group2 <- rep(1:5, 30)

wanted <- function(data, groups, other_params){
data %>% group_by( {{groups}} ) %>% count()
}

not_wanted <- function(data, ..., other_params){
data %>% group_by( ... ) %>% count()
}

works

wanted(iris, groups = Species )
not_wanted(iris, Species, group2)

doesn't work

wanted(iris, groups = vars(Species, group2) )
wanted(iris, groups = c(Species, group2) )
wanted(iris, groups = vars("Species", "group2") )

Error: Column vars(Species, group2) must be length 150 (the number of rows) or one, not 2

答案1

得分: 5

你们把事情弄得太复杂了，这样就可以正常工作：

  1. library(tidyverse)
  3. wanted <- function(data, groups){
  4.   data %>% count(!!!groups)
  5. }
  7. mtcars %>% wanted(groups = vars(mpg, disp, hp))

一个 tibble: 31 x 4

  1.  mpg  disp    hp     n


1 10.4 460 215 1
2 10.4 472 205 1
3 13.3 350 245 1
4 14.3 360 245 1
5 14.7 440 230 1
6 15 301 335 1
7 15.2 276. 180 1
8 15.2 304 150 1
9 15.5 318 150 1
10 15.8 351 264 1

… 其他 21 行

英文:

You guys are over complicating things, this works just fine:

  1. library(tidyverse)
  3. wanted &lt;- function(data, groups){
  4.   data %&gt;%  count(!!!groups)
  5. }
  7. mtcars %&gt;% wanted(groups = vars(mpg,disp,hp))
  9. # A tibble: 31 x 4
  10.      mpg  disp    hp     n
  11.    &lt;dbl&gt; &lt;dbl&gt; &lt;dbl&gt; &lt;int&gt;
  12.  1  10.4  460    215     1
  13.  2  10.4  472    205     1
  14.  3  13.3  350    245     1
  15.  4  14.3  360    245     1
  16.  5  14.7  440    230     1
  17.  6  15    301    335     1
  18.  7  15.2  276.   180     1
  19.  8  15.2  304    150     1
  20.  9  15.5  318    150     1
  21. 10  15.8  351    264     1
  22. # … with 21 more rows

答案2

得分: 0

三重感叹号运算符和rlang包中的parse_quos函数将起作用。有关更多信息，请参见 https://stackoverflow.com/a/49941635/6086135

  1. library(dplyr)
  2. library(magrittr)
  4. iris$group2 <- rep(1:5, 30)
  6. vec <- c("Species", "group2")
  8. wanted <- function(data, groups){
  9.   data %>%  count(!!!rlang::parse_quos(groups, rlang::current_env()))
  10. }
  12. wanted(iris, vec)
  13. #> # A tibble: 15 x 3
  14. #>    Species    group2     n
  15. #>    <fct>       <int> <int>
  16. #>  1 setosa          1    10
  17. #>  2 setosa          2    10
  18. #>  3 setosa          3    10
  19. #>  4 setosa          4    10
  20. #>  5 setosa          5    10
  21. #>  6 versicolor      1    10
  22. #>  7 versicolor      2    10
  23. #>  8 versicolor      3    10
  24. #>  9 versicolor      4    10
  25. #> 10 versicolor      5    10
  26. #> 11 virginica       1    10
  27. #> 12 virginica       2    10
  28. #> 13 virginica       3    10
  29. #> 14 virginica       4    10
  30. #> 15 virginica       5    10
  32. # Created on 2020-01-06 by the reprex package (v0.3.0)
英文:

The triple bang operator and parse_quos from the rlang package will do the trick. For more info, see e.g. https://stackoverflow.com/a/49941635/6086135

<!-- language-all: lang-r -->

  1. library(dplyr)
  3. library(magrittr)
  5. iris$group2 &lt;- rep(1:5, 30)
  8. vec &lt;- c(&quot;Species&quot;, &quot;group2&quot;)
  11. wanted &lt;- function(data, groups){
  12.   data %&gt;%  count(!!!rlang::parse_quos(groups, rlang::current_env()))
  13. }
  15. wanted(iris, vec)
  16. #&gt; # A tibble: 15 x 3
  17. #&gt;    Species    group2     n
  18. #&gt;    &lt;fct&gt;       &lt;int&gt; &lt;int&gt;
  19. #&gt;  1 setosa          1    10
  20. #&gt;  2 setosa          2    10
  21. #&gt;  3 setosa          3    10
  22. #&gt;  4 setosa          4    10
  23. #&gt;  5 setosa          5    10
  24. #&gt;  6 versicolor      1    10
  25. #&gt;  7 versicolor      2    10
  26. #&gt;  8 versicolor      3    10
  27. #&gt;  9 versicolor      4    10
  28. #&gt; 10 versicolor      5    10
  29. #&gt; 11 virginica       1    10
  30. #&gt; 12 virginica       2    10
  31. #&gt; 13 virginica       3    10
  32. #&gt; 14 virginica       4    10
  33. #&gt; 15 virginica       5    10

<sup>Created on 2020-01-06 by the reprex package (v0.3.0)</sup>

答案3

得分: 0

以下是翻译好的部分：

这是另一种避免在函数调用中使用引号的选项。我承认它并不是很漂亮。

  1. library(tidyverse)
  3. wanted <- function(data, groups){
  4.   grouping <- gsub(x = rlang::quo_get_expr(enquo(groups)), pattern = "\\((.*)?\\)", replacement = "\")[-1]
  5.   data %>% group_by_at(grouping) %>% count()
  6. }
  8. iris$group2 <- rep(1:5, 30)
  10. wanted(iris, groups = c(Species, group2) )
  11. #> # A tibble: 15 x 3
  12. #> # Groups:   Species, group2 [15]
  13. #>    Species    group2     n
  14. #>    <fct>       <int> <int>
  15. #>  1 setosa          1    10
  16. #>  2 setosa          2    10
  17. #>  3 setosa          3    10
  18. #>  4 setosa          4    10
  19. #>  5 setosa          5    10
  20. #>  6 versicolor      1    10
  21. #>  7 versicolor      2    10
  22. #>  8 versicolor      3    10
  23. #>  9 versicolor      4    10
  24. #> 10 versicolor      5    10
  25. #> 11 virginica       1    10
  26. #> 12 virginica       2    10
  27. #> 13 virginica       3    10
  28. #> 14 virginica       4    10
  29. #> 15 virginica       5    10

希望这对您有所帮助。

英文:

Here is another option to avoid quotations in the function call. I admit its not very pretty though.

  1. library(tidyverse)
  3. wanted &lt;- function(data, groups){
  4.   grouping &lt;- gsub(x = rlang::quo_get_expr(enquo(groups)), pattern = &quot;\\((.*)?\\)&quot;, replacement = &quot;\&quot;)[-1]
  5.   data %&gt;% group_by_at(grouping) %&gt;% count()
  6. }
  9. iris$group2 &lt;- rep(1:5, 30)
  11. wanted(iris, groups = c(Species, group2) )
  12. #&gt; # A tibble: 15 x 3
  13. #&gt; # Groups:   Species, group2 [15]
  14. #&gt;    Species    group2     n
  15. #&gt;    &lt;fct&gt;       &lt;int&gt; &lt;int&gt;
  16. #&gt;  1 setosa          1    10
  17. #&gt;  2 setosa          2    10
  18. #&gt;  3 setosa          3    10
  19. #&gt;  4 setosa          4    10
  20. #&gt;  5 setosa          5    10
  21. #&gt;  6 versicolor      1    10
  22. #&gt;  7 versicolor      2    10
  23. #&gt;  8 versicolor      3    10
  24. #&gt;  9 versicolor      4    10
  25. #&gt; 10 versicolor      5    10
  26. #&gt; 11 virginica       1    10
  27. #&gt; 12 virginica       2    10
  28. #&gt; 13 virginica       3    10
  29. #&gt; 14 virginica       4    10
  30. #&gt; 15 virginica       5    10

huangapple
  • 本文由 发表于 2020年1月6日 19:52:16
  • 转载请务必保留本文链接：https://go.coder-hub.com/59611638.html
  • dplyr
  • ellipsis
  • grouping
  • r
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