On Fri, Feb 12, 2010 at 4:25 PM, blue sky <bluesky...@gmail.com> wrote: > ?'`' shows the following: > > "Single 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." > > It is not clear to me why double quote is preferred (I don't think > that "character constants are printed using double quotes" should be > the reason, in the sense that single quote can be used for printing if > we want to do so). It seems that double quote and single quote can be > used interchangeably, except that "Single quotes need to be escaped by > backslash in single-quoted strings, and double quotes in double-quoted > strings." > > Could somebody why double quote is preferred?
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. 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. P.S. I do not plan to get into an extended debate on this issue, Peng. (As others have pointed out, it is considered bad form to disguise your identity on this list.) Your opinions on the design of the language have been noted but if you want the language to be redesigned to your specifications, you will need to fork your own version. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
