[R] Regression expression to delete one or more spaces at end of string

[William Dunlap]

First, use [[:blank:]] instead of [:blank:]. that latter matches colon, b,
l,
a, n, and k, the former whitespace.

Second, put + after [[:blank:]] to match one or more of them.

Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Tue, Aug 2, 2016 at 9:46 AM, Dennis Fisher <fisher at plessthan.com> wrote:

> R 3.3.1
> OS X
>
> Colleagues,
>
> I have encountered an unexpected regex problem
>
> I have read an Excel file into R using the readxl package.  Columns names
> are:
>
> COLNAMES        <- c("Study ID", "Test and Biological Matrix", "Subject
> No. ", "Collection Date",
> "Collection Time", "Scheduled Time Point", "Concentration", "Concentration
> Units",
> "LLOQ", "ULOQ", "Comment”)
>
> As you can see, there is a trailing space in “Subject No. “.  I would like
> to delete that space.  The following works:
>         sub(“ $”, “”, COLNAMES)
> However, I would like a more general approach that removes any trailing
> whitespace.
>
> I tried variations such as:
>         sub("[:blank:]$", "", COLNAMES)
> (also, without the $ and ‘space' instead of ‘blank') without success — to
> my surprise, characters other than the trailing space were deleted but the
> trailing space remained.
>
> Guidance on the correct syntax would be appreciated.
>
> Dennis
>
> Dennis Fisher MD
> P < (The "P Less Than" Company)
> Phone / Fax: 1-866-PLessThan (1-866-753-7784)
> www.PLessThan.com
>
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