在R中，如何在使用双卷发括号时选择列？为什么我可以将$运算符与卷发支架使用？

Question

我正在制作一个函数，需要根据用户输入选择特定列。该功能起作用，除了我试图调用用户指定使用$ {{input}}指定的特定列，我收到一条错误消息，即尽管没有，我的函数中有一个额外的'{'。我该如何解决这个问题？为什么我不能在没有触发此错误的情况下用户df $ {{input}}？

在之前起作用的函数

#Sample data and packages

library(dplyr)
library(lubridate)
library(ggplot2)

test <- tibble(Month = ymd(c('1990-01-01', '1990-02-01', '1990-03-01', '1990-04-01', '1990-05-01', '1990-06-01')),
               score_1 = c(1:6),
               score_2 = c(60, 50, 40, 30, NA, 10))

#Working function without using df${{input}} within the geom_line() call

make_chart <- function(data, time_range = c(Week, Month), start_date = NA_Date_) {
  
  data %>%
  ggplot(aes(x = {{time_range}})) + 
    geom_line(data=test[!is.na(test$score_1) & test$Month >= start_date,], aes(y = score_1, colour = "red", linetype = "score 1"), size= 1) + 
    geom_line(data=test[!is.na(test$score_2) & test$Month >= start_date,], aes(y = score_2, colour = "blue", linetype = "score 2"), size= 1)
  
}

make_chart(data = test, start_date = '1990-02-06', time_range = Month)

这是一个

library(dplyr)
library(lubridate)
library(ggplot2)

#Note: the change is within the 2 geom_line lines
make_chart <- function(data, time_range = c(Week, Month), start_date = NA_Date_) {
  
  data %>%
  ggplot(aes(x = {{time_range}})) + 
    geom_line(data=test[!is.na(test$score_1) & test${{time_range}} >= start_date,], aes(y = score_1, colour = "red", linetype = "score 1"), size= 1) + 
    geom_line(data=test[!is.na(test$score_2) & test${{time_range}} >= start_date,], aes(y = score_2, colour = "blue", linetype = "score 2"), size= 1)
  
}

make_chart(data = test, start_date = '1990-02-06', time_range = Month)

示例数据集和 $ {{input}}失败，在这种情况下是什么解决方法。谢谢你！

Answer 1

基于示例，我们将单列用于time_range，filter将数据纳入dat_score1和dat_score2，基于在time_range和'score_1'，'score_2'列中的na元素上，在geom_line中使用该元素，用作data data

library(lubridate)
library(dplyr)
library(ggplot2)

make_chart <- function(data, time_range = Month, start_date = NA_Date_) {
  
  dat_score1 <- data %>%
           filter(complete.cases(score_1), {{time_range}} >= as.Date(start_date))
  dat_score2 <- data %>%
                    filter(complete.cases(score_2),
      {{time_range}} >= as.Date(start_date))
           
  data %>%
  ggplot(aes(x = {{time_range}})) + 
    geom_line(data= dat_score1, 
        aes(y = score_1, colour = "red", 
          linetype = "score 1"), size= 1) + 
    geom_line(data=dat_score2, 
            aes(y = score_2, colour = "blue", linetype = "score 2"), size= 1)
  
}

-testing -testing

make_chart(data = test, time_range = Month, start_date = '1990-02-06' )

-output