Are double "" and single '' quotes (always) interchangeable in R?

Question

This is perhaps rather a minor question...

but just a moment ago I was looking through some code I had written and noticed that I tend to just use ="something" and ='something_else' completely interchangeably, often in the same function.

So my question is: Is there R code in which using one or other (single or double quotes) has different behaviour? Or are they totally synonymous?

@JoshuaUlrich I didn't know there was a `?Quotes` help page thx. my bad. — Stephen Henderson, Dec 13 '13 at 17:45
In the future, try `help.search("topic")`, using your preference of single or double quotes, of course. — Joshua Ulrich, Dec 13 '13 at 17:56
No, I meant `help.search("quote")` or `help.search('quote')`. — Joshua Ulrich, Dec 13 '13 at 20:12
@StephenHenderson you mean `or help.search(" \" ")` LOL as in ["Single quotes need to be escaped by backslash in single-quoted strings, and double quotes in double-quoted strings."](https://stat.ethz.ch/R-manual/R-devel/library/base/html/Quotes.html) — JimLohse, Mar 14 '18 at 17:20

score 30 · Answer 1 · answered Dec 13 '13 at 17:29

30

According to http://stat.ethz.ch/R-manual/R-patched/library/base/html/Quotes.html, "[s]ingle and double quotes delimit character constants. They can be used interchangeably but double quotes are preferred (and character constants are printed using double quotes), so single quotes are normally only used to delimit character constants containing double quotes."

answered Dec 13 '13 at 17:29

Waldir Leoncio

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thx I didn't know it had a help page. Thats quite clear though I think Jorans example is additional info too. – Stephen Henderson Dec 13 '13 at 17:45
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I disagree on the " preference. That requires the shift key, which slows typing and increases hand-strain. I always recommend '. If they are truly interchangeable, that breaks the tie for me. – Bryce Chamberlain Apr 04 '19 at 17:04
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@BryceChamberlain, you have a valid point. I sometimes switch to single quotes for that exact reason, but I end up switching back because habit is a bitch. – Waldir Leoncio Apr 05 '19 at 08:32
What about HTML popups in R? – Wolkuz Jul 31 '22 at 21:07

score 19 · Answer 2 · answered Jul 17 '18 at 15:23

Just for curiosity, there is a further explaination in R-help mailing list for Why double quote is preferred in R:

To avoid confusion for those who are accustomed to programming in the C family of languages (C, C++, Java), where there is a difference in the meaning of single quotes and double quotes. A C programmer reads 'a' as a single character and "a" as a character string consisting of the letter 'a' followed by a null character to terminate the string.

In R there is no character data type, there are only character strings. For consistency with other languages it helps if character strings are delimited by double quotes. The single quote version in R is for convenience.

(Since) On most keyboards you don't need to use the shift key to type a single quote but you do need the shift for a double quote.

score 16 · Accepted Answer · answered Dec 13 '13 at 17:29

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> print(""hi"")
Error: unexpected symbol in "print(""hi"
> print("'hi'")
[1] "'hi'"
> print("hi")
[1] "hi"

answered Dec 13 '13 at 17:29

user1317221_G

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score 1 · Answer 4 · answered May 04 '23 at 08:27

1

"'hi'" == '"hi"'
[1] FALSE

answered May 04 '23 at 08:27

Donald Seinen

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Are double "" and single '' quotes (always) interchangeable in R?

4 Answers4

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