R help - Feb 2012 - gsub syntax help

I have some elements in a vector with extraneous information (e.g. file
name and sample IDs) that I'd like to strip from every element.

For example,  I would like "SPI1.S1.str1.P3.sample.tif"
 "SPI1.S1.STR2.P1.sample.tif" to read  "SPI1.S1.str1.P3"
"SPI1.S1.STR2.P1".

Will someone help me with the syntax in gsub? It needs to be something
like gsub("garbage", "everything except garbage" ,
dataframe,), I think,
but it's the "everything except garbage" that's giving me
trouble.

Thanks
*Ben Caldwell*

	[[alternative HTML version deleted]]

In the example you gave, all that has to be done is
replace ".sample.tif" at the end of the string with "",
which
is easy.
> avec <- c("SPI1.S1.str1.P3.sample.tif",
"SPI1.S1.STR2.P1.sample.tif")
> gsub("\\.sample\\.tif$", "", avec)
[1] "SPI1.S1.str1.P3" "SPI1.S1.STR2.P1"


If your real data are more complex, we need to know what they
look like.

Sarah

On Thu, Feb 2, 2012 at 4:42 PM, Benjamin Caldwell
<btcaldwell at berkeley.edu> wrote:
> I have some elements in a vector with extraneous information (e.g. file
> name and sample IDs) that I'd like to strip from every element.
>
> For example, ?I would like "SPI1.S1.str1.P3.sample.tif"
> ?"SPI1.S1.STR2.P1.sample.tif" to read
?"SPI1.S1.str1.P3" "SPI1.S1.STR2.P1".
>
> Will someone help me with the syntax in gsub? It needs to be something
> like gsub("garbage", "everything except garbage" ,
dataframe,), I think,
> but it's the "everything except garbage" that's giving me
trouble.
>
> Thanks
> *Ben Caldwell*
>
-- 
Sarah Goslee
http://www.functionaldiversity.org