[R] Removing "+" and "?" signs

[jim holtman]

'?' is a metacharacter in a regular expression.  You have to escape it:

> x <- "asdf+,jkl?"
>
> gsub("?", " ", x)
Error in gsub("?", " ", x) : invalid regular expression '?'
In addition: Warning message:
In gsub("?", " ", x) :
  regcomp error:  'Invalid preceding regular expression'
> # escape it
> gsub("\\?", " ", x)
[1] "asdf+,jkl "


On Sun, Nov 22, 2009 at 6:01 PM, Steven Kang <stochastickang at gmail.com> wrote:
> Hi all,
>
>
> I get an error message when trying to replace *+* or *?* signs (with empty
> space) from a string.
>
> x <- "asdf+,jkl?"
>
> gsub("?", " ", x)
>
>
> Error message:
>
> Error in
> gsub("?", " ", x) :
>  invalid regular expression '?'
> In addition: Warning message:
> In gsub("?", " ", x) :
>  regcomp error:  'Invalid preceding regular expression'
>
> Your expertise in resolving this issue would be appreciated.
>
> Thanks.
>
>
>
> Steven
>
>        [[alternative HTML version deleted]]
>
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?