[BioC] regular expression for targets

[DAVID ARTETA GARCIA]

Dear list,

I have a set of gpr files that I have read in using read.maimages(),  
all of them ending with the number and the date of the experiment.  
When I plot the intensities using boxplot() I get the full name of the  
sample, i.e. with these long endings. How can I remove these endings?

> data$targets
                                          FileName
slide 27_3_210408           slide 27_3_210408.gpr
slide 28_3_210408           slide 28_3_210408.gpr
slide 31_3_210408           slide 31_3_210408.gpr
slide 32_3_220408           slide 32_3_220408.gpr
slide 33_3_220408           slide 33_3_220408.gpr
.
.
.

After looking in the archives of BioC and R I tried the following code  
and variations of that but with no luck (I am probably far off the  
right expression). I am trying to store the filenames under a vector  
that can be given as argument to boxplot

> names = sub('(_3_)(\.)','',data$targets,perl=TRUE)

Can anyone help me?

Thanks

D.