Rename column names with gsub and sub

Question

I have been reading about renaming column names using gsub and sub. I want to take various column names 20220427_209944540823_SC835404_12.RCC and truncate to SC835404_12. What am I missing in my code. Currently, I am getting 209944540823_SC835404_12

colnames(expr_counts) <- gsub(c(".RCC"), "", sub("^[^_]*_", "", colnames(expr_counts)))

Answer 1

You can use

colnames(expr_counts) <- sub(".*_(.*_\\d+)\\.RCC$", "\\1", colnames(expr_counts))

See the regex demo .

Details :

• .* - any zero or more chars as many as possible
• _ - an underscore
• (.*_\d+) - Group 1: any zero or more chars as many as possible, _ , one or more digits
• \.RCC - an .RCC string
• $ - end of string.

The replacement is the \1 backreference that replaces the whole match with the Group 1 value.