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

As much as I generally avoid a for loop in R - given you're starting at the beginning and continuing until you find the solution it seemed an easy approach.

It's a bit more intuitive than some of the other examples I think

lcsB <- function(string1, string2) {
    x <- ''
    for (i in 1:nchar(string1)){
        if (substr(string1[1],1,i) == substr(string2[1],1,i)) {
            x <- substr(string1[1],1,i)
        }
        else
            return(x)
        }
    return(x)
}

lcsB("bestelling", "bestelbon")
lcsB("bestelling", "stel")