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

If they all start and end with the same characters and those characters aren't anywhere in the middle part of your string, the gsub expression is simple:

> x <- c("PP_Sample-12.GT","PP_Sample-17.GT")
> gsub('[(PP_)|(.GT)]','',x)
[1] "Sample-12" "Sample-17