java - Regex to remove prefix of a pattern (R) -


i have 2 strings, s , t. how use regex remove copies of prefixes of t end of s?

more specifically, s consists of characters followed copies of t, last 1 may truncated. instance, t abcdef , s asdjb|ak.fvajfabcdefabcdefabcdefabc -- asdjb|ak.fvajf.

additionally, s , t may contain characters special meaning regex engines, such .[]*+()\. i'm working in r, solution in java fine too.

i believe it. it's long.

s <- "asdjb|ak.fvajfabcdefabcdefabcdefabc" t <- "abcdef" want <- "asdjb|ak.fvajf"  sp <- strsplit(t, "")[[1]] pat <- sapply(seq_along(sp), function(i){                 paste(sp[seq_len(i)], collapse = "")             }) pat <- paste0("(", paste(pat, collapse = "|"), ")*$")  result <- gsub(pat, "", s) identical(result, want) [1] true

if want process several vectors, rewrite above function , use sapply. (or lapply.)

repl <- function(x, prefix){     sp <- strsplit(prefix, "")[[1]]     pat <- sapply(seq_along(sp), function(i){                 paste(sp[seq_len(i)], collapse = "")             })     pat <- paste0("(", paste(pat, collapse = "|"), ")*$")     result <- gsub(pat, "", x)     result }  <- rep(s, 10) pref <- rep(t, 10)  sapply(seq_along(where), function(i) repl(where[[i]], pref[[i]]))

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