How can I create colum names in a custom function, pass it to dplyr's select and use purrr's pmap to recycle the custom function?

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英文:

How can I create colum names in a custom function, pass it to dplyr's select and use purrr's pmap to recycle the custom function?

问题

以下代码应该创建一个名为df_test_purrr的列表，其中包含两个数据框。这两个数据框应该分别包含列vs和vs_txt以及am和am_txt。

作为第一步，函数fn_test接受一个数据框的参数dta和一个列的参数col。直接使用参数dta = df_mtcars, col = expr(vs)调用该函数会创建预期的数据框df_test。

  1. # 函数库
  2. library(dplyr)
  3. library(purrr)
  5. # 数据
  6. df_mtcars <- mtcars %>%
  7.   dplyr::mutate(vs_txt = dplyr::case_when(vs == 1 ~ "ABC", T ~ "XYZ"),
  8.                 am_txt = dplyr::case_when(am == 1 ~ "TTT", T ~ "BBB"))
  10. # 用于单列的函数
  11. fn_test <- function(dta, col) {
  12.   {{dta}} %>% 
  13.     dplyr::select({{col}}, as.name( paste0({{col}}, "_txt") ))
  14. }
  16. # 单列的结果
  17. df_test <- fn_test( dta = df_mtcars, col = expr(vs) )
  19. # Purrr
  20. fn_test_purrr <- function() {
  21.   purrr::pmap(list(
  22.     list(df_mtcars, df_mtcars),
  23.     list(expr(vs), expr(am))
  24.   ), fn_test )
  25. }
  27. df_test_purrr <- fn_test_purrr()

定义和调用函数fn_test_purrr会出现错误：

  1. Error in `instrument_base_errors()`:
  2. ! object 'vs' not found
  3. Caused by error:
  4. ! object 'vs' not found
  5. Run `rlang::last_error()` to see where the error occurred.

如何使函数正常工作？

请注意，在我的实际应用程序中，函数fn_test_purrr具有超过两个参数，因此我必须使用purrr的pmap（我猜测）。

英文:

The following code is supposed to create a list, df_test_purrr, with two dataframes. The two dataframes should contain the columns vs, vs_txt and am, am_txt, respectively.

As a first step, the function fn_test takes an argument for a dataframe, dta, and an argument for a column, col. Using the function directly with the argument dta = df_mtcars, col = expr(vs) creates the dataframe df_test as expected.

  1. # Libaries
  2. library(dplyr)
  3. library(purrr)
  5. # Data
  6. df_mtcars &lt;- mtcars %&gt;%
  7.   dplyr::mutate(vs_txt = dplyr::case_when(vs == 1 ~ &quot;ABC&quot;, T ~ &quot;XYZ&quot;),
  8.                 am_txt = dplyr::case_when(am == 1 ~ &quot;TTT&quot;, T ~ &quot;BBB&quot;))
  10. # Function for one column
  11. fn_test &lt;- function(dta, col) {
  12.   {{dta}} %&gt;% 
  13.     dplyr::select( {{col}}, as.name( paste0( {{col}}, &quot;_txt&quot;) ) )
  14. }
  16. # Result for one column
  17. df_test &lt;- fn_test( dta = df_mtcars, col = expr(vs) )
  19. # Purrr
  20. fn_test_purrr &lt;- function() {
  21.   purrr::pmap(list(
  22.     list(df_mtcars, df_mtcars),
  23.     list(expr(vs), expr(am))
  24.   ), fn_test )
  25. }
  27. df_test_purrr &lt;- fn_test_purrr()

Defining and calling the function fn_test_purrr gives the error:

  1. Error in `instrument_base_errors()`:
  2. ! object &#39;vs&#39; not found
  3. Caused by error:
  4. ! object &#39;vs&#39; not found
  5. Run `rlang::last_error()` to see where the error occurred.

How can I make the function work?

Please note that the function fn_test_purrr has more than two arguments in my real-world application such that I must use purrr's pmap (I guess).

答案1

得分: 1

请尝试以下代码：

  1. # 用于单列的函数
  2. fn_test <- function(dta, col) {
  3.   col2 <- paste0(col,'_txt')
  4.   col2 <- col2[col2!='c_txt']
  5.   dta %>%
  6.     dplyr::select( {{col}}, col2) 
  7. }
  9. # 单列的结果
  10. df_test <- fn_test( dta = df_mtcars, col = expr(c(vs,am)) )
  12. # 输出
  14.                     vs am vs_txt am_txt
  15. Mazda RX4            0  1    XYZ    TTT
  16. Mazda RX4 Wag        0  1    XYZ    TTT
  17. Datsun 710           1  1    ABC    TTT
  18. Hornet 4 Drive       1  0    ABC    BBB
  19. Hornet Sportabout    0  0    XYZ    BBB
  20. Valiant              1  0    ABC    BBB
  21. Duster 360           0  0    XYZ    BBB
  22. Merc 240D            1  0    ABC    BBB
  23. Merc 230             1  0    ABC    BBB
  24. Merc 280             1  0    ABC    BBB
  25. Merc 280C            1  0    ABC    BBB
  26. Merc 450SE           0  0    XYZ    BBB
  27. Merc 450SL           0  0    XYZ    BBB
  28. Merc 450SLC          0  0    XYZ    BBB
  29. Cadillac Fleetwood   0  0    XYZ    BBB
  30. Lincoln Continental  0  0    XYZ    BBB
  31. Chrysler Imperial    0  0    XYZ    BBB
  32. Fiat 128             1  1    ABC    TTT
  33. Honda Civic          1  1    ABC    TTT
  34. Toyota Corolla       1  1    ABC    TTT
  35. Toyota Corona        1  0    ABC    BBB
  36. Dodge Challenger     0  0    XYZ    BBB
  37. AMC Javelin          0  0    XYZ    BBB
  38. Camaro Z28           0  0    XYZ    BBB
  39. Pontiac Firebird     0  0    XYZ    BBB
  40. Fiat X1-9            1  1    ABC    TTT
  41. Porsche 914-2        0  1    XYZ    TTT
  42. Lotus Europa         1  1    ABC    TTT
  43. Ford Pantera L       0  1    XYZ    TTT
  44. Ferrari Dino         0  1    XYZ    TTT
  45. Maserati Bora        0  1    XYZ    TTT
  46. Volvo 142E           1  1    ABC    TTT
英文:

Could you please try the below code

  1. # Function for one column
  2. fn_test &lt;- function(dta, col) {
  3.   col2 &lt;- paste0(col,&#39;_txt&#39;)
  4.   col2 &lt;- col2[col2!=&#39;c_txt&#39;]
  5.   dta %&gt;% 
  6.     dplyr::select( {{col}}, col2) 
  7. }
  9. # Result for one column
  10. df_test &lt;- fn_test( dta = df_mtcars, col = expr(c(vs,am)) )
  12. #output
  14.                     vs am vs_txt am_txt
  15. Mazda RX4            0  1    XYZ    TTT
  16. Mazda RX4 Wag        0  1    XYZ    TTT
  17. Datsun 710           1  1    ABC    TTT
  18. Hornet 4 Drive       1  0    ABC    BBB
  19. Hornet Sportabout    0  0    XYZ    BBB
  20. Valiant              1  0    ABC    BBB
  21. Duster 360           0  0    XYZ    BBB
  22. Merc 240D            1  0    ABC    BBB
  23. Merc 230             1  0    ABC    BBB
  24. Merc 280             1  0    ABC    BBB
  25. Merc 280C            1  0    ABC    BBB
  26. Merc 450SE           0  0    XYZ    BBB
  27. Merc 450SL           0  0    XYZ    BBB
  28. Merc 450SLC          0  0    XYZ    BBB
  29. Cadillac Fleetwood   0  0    XYZ    BBB
  30. Lincoln Continental  0  0    XYZ    BBB
  31. Chrysler Imperial    0  0    XYZ    BBB
  32. Fiat 128             1  1    ABC    TTT
  33. Honda Civic          1  1    ABC    TTT
  34. Toyota Corolla       1  1    ABC    TTT
  35. Toyota Corona        1  0    ABC    BBB
  36. Dodge Challenger     0  0    XYZ    BBB
  37. AMC Javelin          0  0    XYZ    BBB
  38. Camaro Z28           0  0    XYZ    BBB
  39. Pontiac Firebird     0  0    XYZ    BBB
  40. Fiat X1-9            1  1    ABC    TTT
  41. Porsche 914-2        0  1    XYZ    TTT
  42. Lotus Europa         1  1    ABC    TTT
  43. Ford Pantera L       0  1    XYZ    TTT
  44. Ferrari Dino         0  1    XYZ    TTT
  45. Maserati Bora        0  1    XYZ    TTT
  46. Volvo 142E           1  1    ABC    TTT

答案2

得分: 1

请检查更新后的代码，该代码返回包含两个数据框的列表。

  1. df_mtcars <- mtcars %>%
  2.   dplyr::mutate(vs_txt = dplyr::case_when(vs == 1 ~ "ABC", T ~ "XYZ"),
  3.                 am_txt = dplyr::case_when(am == 1 ~ "TTT", T ~ "BBB"))
  5. fn_test <- function(dta, col) {
  6.   col2 <- paste0(col,'_txt')
  7.   col2 <- col2[col2!='c_txt']
  9.   if (length(col)==1){
  10.     len=1
  11.     col2 <- paste0(col,'_txt')
  12.   } else if(length(col)>1){
  13.     len <- length(col)-1  
  14.   }
  15.   
  16.   my.list <- list()
  17.   
  18.   for(i in 1:len){
  19.   colx <- paste0({{col}})[i+1]
  20.   colx2 <- col2[i]
  21.   dat <- dta %>% 
  22.     dplyr::select( {{colx}}, colx2) 
  23.     
  24.   my.list[[i]] <- dat
  25.   }
  26.   return(my.list)
  27. }
  29. # 一个列的结果
  30. mylist <- fn_test( dta = df_mtcars, col = expr(c(vs,am)) )
  32. df1 <- as.data.frame(mylist[1])
  33. df2 <- as.data.frame(mylist[2])

这是代码的翻译部分，不包括问题的回答。

英文:

Please check updated code which returns the list with 2 dataframes

  1. df_mtcars &lt;- mtcars %&gt;%
  2.   dplyr::mutate(vs_txt = dplyr::case_when(vs == 1 ~ &quot;ABC&quot;, T ~ &quot;XYZ&quot;),
  3.                 am_txt = dplyr::case_when(am == 1 ~ &quot;TTT&quot;, T ~ &quot;BBB&quot;))
  5. fn_test &lt;- function(dta, col) {
  6.   col2 &lt;- paste0(col,&#39;_txt&#39;)
  7.   col2 &lt;- col2[col2!=&#39;c_txt&#39;]
  9.   if (length(col)==1){
  10.     len=1
  11.     col2 &lt;- paste0(col,&#39;_txt&#39;)
  12.   } else if(length(col)&gt;1){
  13.     len &lt;- length(col)-1  
  14.   }
  15.   
  16.   my.list &lt;- list()
  17.   
  18.   for(i in 1:len){
  19.   colx &lt;- paste0({{col}})[i+1]
  20.   colx2 &lt;- col2[i]
  21.   dat &lt;- dta %&gt;% 
  22.     dplyr::select( {{colx}}, colx2) 
  23.     
  24.   my.list[[i]] &lt;- dat
  25.   }
  26.   return(my.list)
  27. }
  29. # Result for one column
  30. mylist &lt;- fn_test( dta = df_mtcars, col = expr(c(vs,am)) )
  32. df1 &lt;- as.data.frame(mylist[1])
  33. df2 &lt;- as.data.frame(mylist[2])

答案3

得分: 0

以下是您要翻译的内容：

对于那些感兴趣的人，我提出了一种不同的方法，也适用于我的目的：

库

library(dplyr)
library(purrr)

数据

df_mtcars <- mtcars %>%
dplyr::mutate(vs_txt = dplyr::case_when(vs == 1 ~ "ABC", T ~ "XYZ"),
am_txt = dplyr::case_when(am == 1 ~ "TTT", T ~ "BBB"))

用于一个列的函数

fn_test <- function(dta, var) {
dta %>%
dplyr::select( {{var}} )
}

函数调用

test <- fn_test(dta = df_mtcars, var = c("vs", "vs_txt"))

Purrr

fn_test_purrr <- function() {
purrr::pmap(
list(
list(df_mtcars, df_mtcars),
list(c("vs", "vs_txt"), c("am", "am_txt"))
), fn_test
)
}

函数调用

test_purrr <- fn_test_purrr()

结果

test_purrr[[1]]
test_purrr[[2]]

英文:

For those who are interested, I came up with a different approach that also works for my purpose:

  1. # Libaries
  2. library(dplyr)
  3. library(purrr)
  5. # Data
  6. df_mtcars &lt;- mtcars %&gt;%
  7.   dplyr::mutate(vs_txt = dplyr::case_when(vs == 1 ~ &quot;ABC&quot;, T ~ &quot;XYZ&quot;),
  8.                 am_txt = dplyr::case_when(am == 1 ~ &quot;TTT&quot;, T ~ &quot;BBB&quot;))
  11. # Function for one column
  12. fn_test &lt;- function(dta, var) {
  13.   dta %&gt;% 
  14.     dplyr::select( {{var}} )
  15. }
  17. # Function call
  18. test &lt;- fn_test(dta = df_mtcars, var = c(&quot;vs&quot;, &quot;vs_txt&quot;))
  20. # Purrr
  21. fn_test_purrr &lt;- function() {
  22.   purrr::pmap(
  23.     list(
  24.       list(df_mtcars, df_mtcars),
  25.       list(c(&quot;vs&quot;, &quot;vs_txt&quot;), c(&quot;am&quot;, &quot;am_txt&quot;))
  26.     ), fn_test
  27.   )
  28. }
  30. # Function call
  31. test_purrr &lt;- fn_test_purrr()
  33. # Results
  34. test_purrr[[1]]
  35. test_purrr[[2]]

huangapple
  • 本文由 发表于 2023年6月26日 22:45:02
  • 转载请务必保留本文链接：https://go.coder-hub.com/76557763.html
  • dplyr
  • purrr
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