I have to implement a RC4 algorithim in R programming, I am havng issues with the last line K[x] <- key4[(x %% numchar)]. I keep getting an error "Error in K[x] <- key4[(x%%7)] : replacement has length zero". Please help. The code I have so far is written below.

key3 <- ("puzzles")

numchar <- nchar(key3, type = "bytes")

S <- for(i in 1:256){ print(i) } K <- vector(mode = "integer", length = 256) for (x in 1:256){ S[x] <- x K[x] <- key4[(x %% numchar)] }