pander包中的Pandoc.convert()函数 出现错误

carcar

我想利用pander包中的Pandoc.convert()函数将md文件转换为docx或HTML格式
> Pandoc.convert("XML.md",open=TRUE,format="docx")

出现错误：
You may install Pandoc easily with "install.pandoc()" from the "installr" package.
Error in Pandoc.convert("XML.md", open = TRUE, format = "docx") :
  It seems Pandoc is not installed or path of binary is not found. Did you restarted R after Pandoc install? See installation details by running:


         readLines(system.file('includes/html/footer.html', package='pander'))




这是怎么回事呢？