[R] Removing characters and periods from character strings

[Greg Snow]

To remove all numbers and periods at the end do:

> vars <- sub("[0-9.]+$", "", pick )

If there are other periods that this does not remove (not at the end) then you can do a second pass:

> vars <- sub("\\.", "", vars)

Part of the reason that your code for the period does not work is that an unescaped period matches any single character (hence the "\\." in the above).

You may also want to look at the unique function if you want to remove the duplicates that result.

Hope this helps,


--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of John Poulsen
> Sent: Wednesday, October 15, 2008 1:43 PM
> To: r-help at r-project.org
> Subject: [R] Removing characters and periods from character strings
>
> Hello R-users,
>
> I have code that gives me the important variables from an analysis.  I
> need to input these variables into a different analysis.  To do this, I
> need to modify them slightly... 1) remove all numbers at the end of the
> variables, 2) remove all periods.
>
> I tried to do it with the awkward code below.  It works to remove all
> the numbers, but when I try to remove the period everything is lost.
>
> Does anyone have a solution?  And perhaps a more elegant way?
>
> pick=c("(Intercept)", "Clear", "factor(Hab)3", "factor(Hab)4",
> "factor(Hab)5","factor(Hab)7", "factor(Log)1", "Hunt", "Pop",
> "s(PrimRd).1", "s(PrimRd).2", "Unlog", "Xcoord", "Ycoord")
>
>   vars=as.character(as.vector(strsplit(pick,"1")))
>     vars=unique(as.character(as.vector(strsplit(vars,"2"))))
>     vars=unique(as.character(as.vector(strsplit(vars,"3"))))
>     vars=unique(as.character(as.vector(strsplit(vars,"4"))))
>     vars=unique(as.character(as.vector(strsplit(vars,"5"))))
>     vars=unique(as.character(as.vector(strsplit(vars,"7"))))
>     vars=unique(as.character(as.vector(strsplit(vars,"."))))
>
> Thanks for your help!
> John
>
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