将参数从命令行传递到R降价文档

Question

我正在从命令行运行降价报告:

R -e "rmarkdown::render('ReportUSV1.Rmd')"

这份报告是在R工作室完成的,顶部看起来像

---
title: "My Title"
author: "My Name"
date: "July 14, 2015"
output: 
  html_document:
   css: ./css/customStyles.css
---


```{r, echo=FALSE, message=FALSE}

load(path\to\my\data)
```

我想要的是能够将标题和文件路径一起传递到shell命令,以便它生成原始报告,结果是不同的filename.html.

谢谢!

Answer 1

有几种方法可以做到.

您可以在YAML中使用backtick-R块并在执行render之前指定变量:

---
title: "`r thetitle`"
author: "`r theauthor`"
date: "July 14, 2015"
---

foo bar.

然后:

R -e "thetitle='My title'; theauthor='me'; rmarkdown::render('test.rmd')"

或者您可以commandArgs()直接在RMD中使用并在以下情况下将其输入--args:

---
title: "`r commandArgs(trailingOnly=T)[1]`"
author: "`r commandArgs(trailingOnly=T)[2]`"
date: "July 14, 2015"
---

foo bar.

然后:

 R -e "rmarkdown::render('test.rmd')" --args "thetitle" "me"

这里如果你命名为args R -e ... --args --name='the title',你commandArgs(trailingOnly=T)[1]的字符串是"--name = foo" - 它不是很聪明.

在任何一种情况下,我想你会想要某种错误检查/默认检查.我通常会编写一个编译脚本,例如

# compile.r
args <- commandArgs(trailingOnly=T)
# do some sort of processing/error checking
#  e.g. you could investigate the optparse/getopt packages which
#   allow for much more sophisticated arguments e.g. named ones.
thetitle <- ...
theauthor <- ...
rmarkdown::render('test.rmd')

然后R compile.r --args ...以我编写脚本要处理的格式运行提供参数.