问题
I'm having working directory issues when using knitr with parent and child R Markdown documents and external chunks from my R code. I've described the situation and provided links to my code here: https://github.com/yihui/knitr/issues/38 (the issue is closed, but relevant, so I decided to leave my comment there). Would appreciate your help on this! (A copy of this has also been posted to knitr Google Groups.)
来源：https://stackoverflow.com/questions/25705821/working-directory-issues-with-knitr-parent-and-child-r-markdown-documents