rmarkdown error "attempt to use zero-length variable name"

Question

When i generate a new rmarkdown file (or open existing rmarkdown-files) and try to run a rmarkdown chunk, i get this error: "Error: attempt to use zero-length variable name". I have Win10 and did a fresh install of R and Rstudio yesterday. What did i miss? Where does this error come from?

```{r cars}
summary(cars)
```

```{r cars} Error: attempt to use zero-length variable name

Answer 1

Putting this as an answer for visibility: this happens if you try to run by selecting all in the Rmd and pressing enter like you would with a normal R script. RStudio tries to run this all as R code, including the markdown parts, leading to the errors you saw.

You can avoid this by running an individual chunk by clicking the green play button or by selecting one of the run options in the dropdown at the top of the Rmd editor.