如何使用dplyr通过2个列集将内部联接的列名作为变量传递 [英] How to pass column names for inner join by 2 column sets as variables with dplyr

问题描述

我一直在研究各种建议的方法来将列名作为变量传递，例如使用bang（!! xvar），as.name（xvar）和其他各种方法，但我无法使用它。

I've been looking at various suggested approaches for passing a column name as variable such as using bang bang (!!xvar), as.name(xvar) and various others but I can't get it to work.

有人知道如何在下面的管道中将 mtcars 中使用的列名作为变量传递吗？

Does anyone know how to pass the column names used from mtcars in the pipeline below as variables?

即

xvar<-'mpg'

yvar<-'cyl'

构建我的数据的虚拟对象以进行连接以确定已选择的哪几行切换T <-> F

to build a dummy of my data to do the join with used to determine which rows of Selected to switch T <-> F

newData <- data.frame(trace = 0, point = 1:6, 'x' = unlist(mtcars[ c(1,3,5,9:11) ,1]),  y = unlist(mtcars[ c(1,3,5,9:11) ,c('cyl')]))
rownames(newData) <- NULL

mtcars$Selected <- T

mtcars %>%
  mutate(Selected = if_else(row_number() %in% {mtcars %>% 
      mutate(rn = row_number()) %>% 
      inner_join(distinct(newData), by = c('mpg' = "x", "cyl" = 'y')) %>% 
      pull(rn)}, !Selected, Selected))

但我需要通过'mpg'和'cyl'作为变量： xpar 和 ypar
，因为它们来自于菜单中的下拉菜单发光的应用程序

but I need to pass 'mpg' and 'cyl' as variables: xpar and ypar since they are coming from drop down menus in a Shiny App

xpar<-'mpg'＃（input $ xpa闪亮的应用程序中的r_selector）

ypar<-'cyl'＃（闪亮的应用程序中的input $ ypar_selector）

推荐答案

一种选择是使用 setNames

 ...
 inner_join(distinct(newData), by = setNames(c('x', 'y'), c(xvar, var)))
 ...

完整代码

mtcars %>% 
       mutate(rn = row_number()) %>% 
       inner_join(distinct(newData), by = setNames(c('x', 'y'), c(xvar, yvar))) %>% 
       pull(rn)
#[1]  1  2  3  3  5  9  9 10 11

实际完整代码：

mtcars %>%
  mutate(Selected = if_else(row_number() %in% {
      mtcars %>% 
        mutate(rn = row_number()) %>% 
        inner_join(distinct(newData), by = setNames(c('x', 'y'), c(xvar, yvar))) %>% 
        pull(rn)
       },
        !Selected, Selected))

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