[R] splitting sample names

[David Winsemius]

On Aug 18, 2011, at 5:43 PM, 1Rnwb wrote:

> I have a data frame like this
> xx<- 
> data 
> .frame 
> (cbind 
> (Sample 
> =c('Ctrl_6h','1+0_6h','1+200_6h','1+5k_6h','Ctrl_5K_6h','ConA_6h'),
>                 IFIT1=c(24,25,24.7,24.5,24.2,24.8)))
>
> grep('[[:digit:]]h',xx$Sample)
>
> yy<-xx$Sample
>
> strsplit(yy,"_")
>

You are getting tangled up because of stringsAsFactor + TRUE by  
default. (The cbind is not needed and may have been confusing things  
as well.)

  xx <- 
data 
.frame 
(Sample 
=c('Ctrl_6h','1+0_6h','1+200_6h','1+5k_6h','Ctrl_5K_6h','ConA_6h'),
                  IFIT1=c(24,25,24.7,24.5,24.2,24.8),  
stringsAsFactors=FALSE)

  sub('(^.+)([[:digit:]]h$)', "\\2", xx$Sample)
1] "6h" "6h" "6h" "6h" "6h" "6h"

  yy<-xx$Sample

  strsplit(yy,"_")
#--------------
[[1]]
[1] "Ctrl" "6h"

[[2]]
[1] "1+0" "6h"

[[3]]
[1] "1+200" "6h"

[[4]]
[1] "1+5k" "6h"

[[5]]
[1] "Ctrl" "5K"   "6h"

[[6]]
[1] "ConA" "6h"


Try instead to use these results to guide you
> I have to extract the time information separated by '_' in the  
> sample names,
> i tried grep and strsplit, it looks that i am not providing some  
> information
> correctly. I would appreciate if someone can point me to the correct  
> way.
> Thanks
> Sharad
>
> --
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>
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David Winsemius, MD
West Hartford, CT