基于数据集信息的 ar 函数出错

Question

我有这个数据集：

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df <- data.frame( raca = c("Nel","Nel","Nel", "Nel","Angus","Angus","Angus","Angus"),\n                  marmo = c(350, 320, 330, 400, 800, 820, 450, NA))\n

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我想做描述性统计。我使用了这段代码：

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df %>%\n  group_by(raca) %>%\n  dplyr::summarise(across(1,~data.frame(M\xc3\xa9dia =round(mean(.,na.rm=TRUE,digits=2),digits = 2),\n                                                    N = length(.),\n                                                    DP = round(sd(.,na.rm=TRUE),digits = 2),\n                                                    Min = min(.,na.rm=TRUE),\n                                                    Max = max(.,na.rm=TRUE),\n                                                    `Coef Varia\xc3\xa7\xc3\xa3o` = round(sd(., na.rm=TRUE)/mean(.,na.rm=TRUE)*100,digits=2)))) %>%\n  pivot_longer(-raca) %>% arrange(name,raca)\n

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并且运作良好。但我想要一个函数，我尝试了这段代码：

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desc_function <- function(a,b, c)   { a %>%\n    group_by(a[,b]) %>%\n    dplyr::summarise(across(a[,c],~data.frame(M\xc3\xa9dia =round(mean(.,na.rm=TRUE,digits=2),digits = 2),\n                                              N = length(.),\n                                              DP = round(sd(.,na.rm=TRUE),digits = 2),\n                                              Min = min(.,na.rm=TRUE),\n                                              Max = max(.,na.rm=TRUE),\n                                              `Coef Varia\xc3\xa7\xc3\xa3o` = round(sd(., na.rm=TRUE)/mean(.,na.rm=TRUE)*100,digits=2)))) %>%\n    pivot_longer(a[,b]) %>% arrange(name,a[,b])}\n\n\ndesc_function(df, "raca", "marmo")\n

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但发生了这个错误：

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 Error: Problem with summarise() input ..1.\ni ..1 = across(...).\nx Selections can't have missing values.\ni The error occurred in group 1: a[, b] = "Angus".\nRun rlang::last_error() to see where the error occurred.\n

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Answer 1

我同意 shafee 的观点，阅读如何编程dplyr略有不同。

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这是您的操作方法（直接调整您的代码）

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desc_function <- function(a,b, c)   { a %>%\n    group_by(.data[[b]]) %>%\n    dplyr::summarise(across(.data[[c]],~data.frame(M\xc3\xa9dia =round(mean(.,na.rm=TRUE,digits=2),digits = 2),\n                                              N = length(.),\n                                              DP = round(sd(.,na.rm=TRUE),digits = 2),\n                                              Min = min(.,na.rm=TRUE),\n                                              Max = max(.,na.rm=TRUE),\n                                              `Coef Varia\xc3\xa7\xc3\xa3o` = round(sd(., na.rm=TRUE)/mean(.,na.rm=TRUE)*100,digits=2)))) %>%\n    pivot_longer(-.data[[b]]) %>% arrange(name,.data[[b]])}\n\n\ndesc_function(df, "raca", "marmo")\n

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注意使用 来.data[[b]]从函数中调用字符串变量

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或者传递未包含在字符串中的变量，如下所示

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desc_function <- function(a,b, c)   { a %>%\n    group_by({{b}}) %>%\n    dplyr::summarise(across({{c}},~data.frame(M\xc3\xa9dia =round(mean(.,na.rm=TRUE,digits=2),digits = 2),\n                                              N = length(.),\n                                              DP = round(sd(.,na.rm=TRUE),digits = 2),\n                                              Min = min(.,na.rm=TRUE),\n                                              Max = max(.,na.rm=TRUE),\n                                              `Coef Varia\xc3\xa7\xc3\xa3o` = round(sd(., na.rm=TRUE)/mean(.,na.rm=TRUE)*100,digits=2)))) %>%\n    pivot_longer(-{{b}}) %>% arrange(name,{{b}})}\n\n\ndesc_function(df, raca, marmo)\n

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这次使用{{b}}等。

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如上所述，所有内容均记录在https://dplyr.tidyverse.org/articles/programming.html中

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