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

why not add another! and hack at it so the answer is different than everyone elses!

largestStartSubstr<-function(word1, word2){ 
    word1vec<-unlist(strsplit(word1, "", fixed=TRUE))
    word2vec<-unlist(strsplit(word2, "", fixed=TRUE))
    indexes<-intersect(1:nchar(word1), 1:nchar(word2))
    bools<-word1vec[indexes]==word2vec[indexes]
    if(bools[1]==FALSE){
        ""
    }else{
        lastChar<-match(1,c(0,diff(cumsum(!bools))))-1
        if(is.na(lastChar)){
            lastChar<-indexes[length(indexes)]
        }
        substr(word1, 1,lastChar)
    }
}

word1 <- "bestselling"
word2<- "bestsel"

largestStartSubstr(word1, word2)
#[1] "bestsel"

word1 <- "bestselling"
word2<- "sel"

largestStartSubstr(word1, word2)
#[1] ""