Extract a string between patterns/delimiters in R

Question

I have variable names in the form:

PP_Sample_12.GT

or

PP_Sample-17.GT

I\'m trying to use string split to

Answer 1

Here's a gsub that will extract everything after the first _ and before the last .

x<-c("PP_Sample-12.GT","PP_Sample-17.GT")
gsub(".*_(.*)\\..*","\\1", x, perl=T)