如何在 Rmd 中使用 Latex' \\newcommand ？

Question

我想做以下工作

---
title: "Untitled"
author: "SQC"
date: "21 September 2018"
output: html_document
---

\newcommand{\short}{AreallylongwordIhavetotypefrequently}

# My Test
I would like to write \short which does not work, $\short$ however is close... 
Snippets do not work in Rmd plain text (= Rstudio's "Shift", see link below).

但我找不到解决办法。 如果周围有东西就好了！ 以下链接很有帮助，但没有提出解决方案： pandoc doc ， Rmd 公式中的 \\newcommand和RStudio 片段。

Answer 1

改用 R 怎么样：

---
title: "Untitled"
author: "SQC"
date: "21 September 2018"
output: html_document
---

```{r, include = FALSE}
short <- "AreallylongwordIhavetotypefrequently"
```

# My Test
I would like to write `r short` instead ...

Answer 2

如果你仍然需要在\\newcommand使用 LaTeX 定义一个\\newcommand newcommand，你可以这样做，例如

Some text with the following equation:

\begin{equation} \newcommand{\matr}[1]{\mathbf{#1}}
\matr{Y} =
\begin{pmatrix}
\matr{y_1} \\
\matr{y_2} \\
\end{pmatrix}
\end{equation}

```{r}
y1 + y2
```

请注意，必须加载bm包才能使其工作，例如，通过在 YAML 标头中使用它：

---
title: "My R Report" 
author: "Me" 
date: "2020-01-31" 
header-includes: 
  - \usepackage{bm} 
output: 
  pdf_document: 
    toc: true 
    number_sections: true
---