r - 交互式 ggplotly 图不是从 R 中 Rmd 文件中的 for 循环内部绘制的

Question

我试图从 R markdown ( ) 文件ggplotly的内部for循环中绘制一系列交互式图形。.Rmd我的.Rmd文件内容：

---
title: "Untitled"
output: html_document
---

```{r}
library(ggplot2) # for plots
library(plotly)  # for interactive plots

# Convert 4 variables to factor variables:
factor_vars <- c("vs", "am", "gear", "carb")
mtcars[factor_vars] <- data.frame(Map(as.factor, mtcars[factor_vars])) 



for (VAR in factor_vars) {
    cat(paste("Factor variable:", VAR))
    # Contents of "VAR" changes inside the loop
    p <- ggplot(mtcars, aes_string(x = "mpg", y = "wt", color = VAR)) + geom_point()

    # Print an interactive plot
    print(ggplotly(p))
}

```

我按下Knit HTML按钮RStudio。不幸的是，文件中没有出现任何交互式绘图.html。

问题：为什么不绘制图表？以及如何结合文件中的for循环创建交互式绘图Rmd？

ps 如果我使用print(p)而不是print(ggplotly(p))，ggplot2绘图会出现在结果.html文件中。

Answer 1

基于this github issue，您应该能够执行以下操作：

  ---
  title: "Untitled"
  output: html_document
  ---

  ```{r, message = F}
  library(ggplot2) # for plots
  library(plotly)  # for interactive plots

  # Convert 4 variables to factor variables:
  factor_vars <- c("vs", "am", "gear", "carb")
  mtcars[factor_vars] <- data.frame(Map(as.factor, mtcars[factor_vars])) 

  plt <- htmltools::tagList()
  i <- 1
  for (VAR in factor_vars) {

      # Contents of "VAR" changes inside the loop
      p <- ggplot(mtcars, aes_string(x = "mpg", y = "wt", color = VAR)) + 
        geom_point() + 
        ggtitle(paste("Factor variable:", VAR))


      # Print an interactive plot
      # Add to list
      plt[[i]] <- as.widget(ggplotly(p))
      i <- i + 1
  }

  ```

  ```{r, echo = F}
  plt
  ```