R markdown 链接在编织为 pdf 时未格式化为蓝色

Question

出于某种原因，我的 R markdowns (rmd) 中没有链接被格式化为蓝色。将下面的简单 rmd 编织为 pdf 会使文本颜色为黑色。只有当鼠标悬停在它上面时，才会意识到它实际上是一个链接。将其编织为 html 将使链接变为蓝色。当然我可以使用 latex 包装，但我想知道为什么会这样？

sessionInfo() R version 3.3.0 (2016-05-03) Platform: x86_64-w64-mingw32/x64 (64-bit) Running under: Windows 7 x64 (build 7601) Service Pack 1 loaded via a namespace (and not attached): knitr_1.15

RStudio 1.0.44

---
title: "R Notebook"
output:
  pdf_document: default
  html_notebook: default
---

```{r, echo=F}
# tex / pandoc options for pdf creation
x <- Sys.getenv("PATH")
y <- paste(x, "E:\\miktex\\miktex\\bin", sep=";")
Sys.setenv(PATH = y)
```

[link](www.rstudio.com)

Answer 1

添加 urlcolor: blue到 yaml。

---
title: "R Notebook"
output:
  pdf_document: default
  html_notebook: default
urlcolor: blue
---

```{r, echo=F}
# tex / pandoc options for pdf creation
x <- Sys.getenv("PATH")
y <- paste(x, "E:\\miktex\\miktex\\bin", sep=";")
Sys.setenv(PATH = y)
```

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