在闪亮/ flexdashboards中，如何通过multiple = TRUE的输入更改列的值？

Question

当multiple = TRUE 时，我似乎无法弄清楚如何在 flexdashboard/shiny 中更改数据框中列的值。在下面的示例中，我可以通过单独选择 x 和 y 来更改它们。我想要完成的是当我同时选择 x 和 y 时，df$x 变为 3，df$y 变为 2。

但是当两者都被选中时，只有第一个被选中的会被改变。

---
title: "Test"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    social: menu
    source_code: embed
    runtime: shiny
---

```
library(flexdashboard)
library(shiny)
library(DT)

df <- data.frame(
  x = 1:10,
  y = 1:10)

selectInput("var", label = "Change:", 
        choices =  list("no change", "x","y"), 
        multiple =TRUE,
        selected = "no change"
        )

renderDataTable({
  if(input$var == "no change")  {df <- df} 
  if(input$var %in% "x")  {df$x <- 3}  
  if(input$var %in% "y")  {df$y <- 2} 
  return(df)
   })
```

任何帮助将不胜感激。

Answer 1

对于上下文，下面是上面代码的输出快照，上面没有应用程序输出：

图片 0

---

您几乎就在那里——只是在最后两个if 之前缺少else，以及相应的换行符（类似地，see this）。

---
title: "Please remember to make [reprex posts](https://stackoverflow.com/help/minimal-reproducible-example) :)"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
library(flexdashboard)
library(shiny)
library(DT)
library(tidyverse)
```

## R Markdown

This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see <http://rmarkdown.rstudio.com>.

When you click the **Knit** button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:

```{r now-including-else}

df <- data.frame(
  x = 1:10,
  y = 1:10)

selectInput("var", label = "Change:", 
            choices =  list("no change", "x","y"), 
            multiple =TRUE,
            selected = "no change"
            )

renderDataTable({
  if(input$var == "no change")  {
    df <- df
  }
  else if(input$var %in% "x")  {
    df$x <- 3
  }
  else if(input$var %in% "y")  {df$y <- 2} 
  return(df)
})
```

附： Reprex posts.

---

建议的代码输出的一些快照：

图片 1

图片 2

图 3