rmarkdown中的if块内部的几个ggplotly数字

Question

我无法从 rmarkdown 生成 html 文件，该文件显示在给定代码块的 if 块内创建的两个或多个 ggplotly 图。

我的 MWE rmarkdown 源码如下：

---
title: Several ggplotly figures from within if block in rmarkdown
author: "Mauricio Calvao"
date: "February 27, 2017"
output:
    html_document: default
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r}
library(ggplot2)
library(plotly)
```


## Outside if block:

I can have rmarkdown generate an html document with two ggplotly plots, outside of an if block in a given chunk:

```{r}
ggplotly(qplot(data = pressure, x = temperature, y = pressure))
ggplotly(qplot(data = pressure, x = pressure, y = temperature))
```

## Inside if block:

However, when I try the same code inside an if block, only the last plot shows up in the html document:

```{r}
if (TRUE) {
ggplotly(qplot(data = pressure, x = temperature, y = pressure))
ggplotly(qplot(data = pressure, x = pressure, y = temperature))
}
```



**How do I print two (or more plots, for that matter) from within an if block in the html document???**

The above is a MWE, but, in fact, in a more general setting I would have a large number of plots to be printed depending on several if else blocks...

欢迎提出建议！！

Answer 1

现在可以从plotly reference 获得答案。 简而言之，您可以使用：

• 子图：

  if (TRUE) {
   p1= ggplotly(qplot(data = pressure, x = temperature, y = pressure))
   p2= ggplotly(qplot(data = pressure, x = pressure, y = temperature))
   subplot(p1, p2)
  }
  

• 或标签列表

  if (TRUE) {
   p1= ggplotly(qplot(data = pressure, x = temperature, y = pressure))
   p2= ggplotly(qplot(data = pressure, x = pressure, y = temperature))
   htmltools::tagList(list(p1, p2))
  }