使用 "plot" 或 "plt" 前缀块标签修改图形标题

Question

我最近开始为块标签添加前缀以帮助我确定预期的输出；即，"plot" 表示情节，"tbl" 表示 table，等等

今天早上我试图在情节中添加 fig.cap。标题将无法正确显示；它看起来像这样：

(#fig:plt_cars)This caption will not display correctly.

我希望这样：

Figure 1: This caption will display correctly.

经过反复试验，我发现添加 "plot" 或 "plt" 作为块标签的前缀会导致此问题。

以下示例对此进行了演示。

---
title: Test Post
author: Tim Trice
date: '2017-10-14'
slug: test-post
categories: []
tags: []
---

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

```{r}
data(cars)
```

```{r cars, fig.cap = "This caption will display correctly."}
ggplot(cars, aes(x = speed, y = dist)) + geom_point()
```

```{r plt_cars, fig.cap = "This caption will not display correctly."}
ggplot(cars, aes(x = speed, y = dist)) + geom_point()
```

```{r plot_cars, fig.cap = "Nor will this caption display correctly."}
ggplot(cars, aes(x = speed, y = dist)) + geom_point()
```

所有字幕都可以在普通 Rmd 文档中正常呈现；但不在 blogdown 中。

我正在使用 blogdown 0.1。

我已经在 Debian 和 Windows 上验证了这一点，但目前只有 R 3.4.0。

谁能告诉我为什么我不能使用这些前缀？

编辑：它不是前缀，而是使用定界符“_”或“.”。

这些例子不起作用：

```{r test_cars, fig.cap = "Nor will this caption display correctly."}
ggplot(cars, aes(x = speed, y = dist)) + geom_point()
```

```{r test.cars, fig.cap = "Nor will this caption display correctly."}
ggplot(cars, aes(x = speed, y = dist)) + geom_point()
```

```{r c_a_r_s, fig.cap = "Nor will this caption display correctly."}
ggplot(cars, aes(x = speed, y = dist)) + geom_point()
```

编辑 2：同样的问题适用于 knitr::kable 个字幕。

```{r tblcars}
kable(cars, caption = "This table caption works.")
```

```{r tbl_cars}
kable(cars, caption = "This table caption does not work.")
```

Answer 1

来自 Appendix A of the blogdown book:

[...] and you need to read Chapter 2 of the bookdown book (Xie 2016) to learn more about these [R Markdown] features.

来自Section 2.4 of the bookdown book：

If you want to cross-reference figures or tables generated from a code chunk, please make sure the chunk label only contains alphanumeric characters (a-z, A-Z, 0-9), slashes (/), or dashes (-).

如果您想对数字进行编号或交叉引用，则不支持下划线。

使用 "plot" 或 "plt" 前缀块标签修改图形标题

Prefixing chunk label with "plot" or "plt" modifies figure caption

r

blogdown