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

This grabs the 2nd element of each part of the list that was split and then simplifies it into a vector by subsetting the function [, using sapply to call this function for each element of the original list.

x <- c('PP_Sample_12.GT', 'PP_Sample-17.GT')
sapply(strsplit(x, '(?:_(?=\\D)|\\.GT)', perl = T), '[', 2)

[1] "Sample_12" "Sample-17"