Multiline Comment Workarounds?


Question

I (sort of) already know the answer to this question. But I figured it is one that gets asked so frequently on the R Users list, that there should be one solid good answer. To the best of my knowledge there is no multiline comment functionality in R. So, does anyone have any good workarounds?

While quite a bit of work in R usually involves interactive sessions (which casts doubt on the need for multiline comments), there are times when I've had to send scripts to colleagues and classmates, much of which involves nontrivial blocks of code. And for people coming from other languages it is a fairly natural question.

In the past I've used quotes. Since strings support linebreaks, running an R script with

"
Here's my multiline comment.

"
a <- 10
rocknroll.lm <- lm(blah blah blah)
 ...

works fine. Does anyone have a better solution?

1
103
1/27/2016 11:33:28 AM

Accepted Answer

This does come up on the mailing list fairly regularly, see for example this recent thread on r-help. The consensus answer usually is the one shown above: that given that the language has no direct support, you have to either

  • work with an editor that has region-to-comment commands, and most advanced R editors do
  • use the if (FALSE) constructs suggested earlier but note that it still requires complete parsing and must hence be syntactically correct
47
8/5/2009 1:43:25 PM

You can do this easily in RStudio:

select the code and click CTR+SHIFT+C to comment/uncomment code.


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