R: find largest common substring starting at the beginning

Question

I\'ve got 2 vectors:

word1 <- \"bestelling\"   
word2 <- \"bestelbon\"

Now I want to find the largest common substring that starts at the

Answer 1

Here's another function that seems to work.

foo <- function(word1, word2) {
    s1 <- substring(word1, 1, 1:nchar(word1))
    s2 <- substring(word2, 1, 1:nchar(word2))
    if(length(w <- which(s1 %in% s2))) s2[max(w)] else character(1)
}

foo("bestelling", "bestelbon")
# [1] "bestel"
foo("bestelling", "stel")
# [1] ""
foo("bestelbon", "bestieboop")
# [1] "best"
foo("stel", "steal")
# [1] "ste"