R/lenACSstrStrict.r

In calACS: Calculations for All Common Subsequences

# Internal function:
# Calculate the length of the common subsequences between 2 input strings
# param strA First string
# param strB Second string
# param sep Delimiter separating each items in a sequence
# param dropFirstItem Boolean. If true, the first item in each sequence is excluded from counting all subsequences
# param ignoreLenOneSubseq Boolean. If true, all length one subequences are not counted as common subsequences
# return a vector containing the length of each common subsequence


lenACSstrStrict <- function(strA, strB, sep="-", dropFirstItem=FALSE, ignoreLenOneSubseq=FALSE){
#     #test
#     strA <- 'aa-b-c'
#     strB <- 'aa-b-c-d'
#     sep='-'
#     dropFirstItem=FALSE
#     i=4
#     i=5
#     i=6

  lenACS <- NULL #count the empty set as one common subsequence

  A <- unlist(strsplit(strA, sep))
  B <- unlist(strsplit(strB, sep))

  if (dropFirstItem){
    A <- A[-1]
    B <- B[-1]
  }

  listSubseq <- GeneratePossibleSubsequences(A, ignoreLenOneSubseq)

  for(i in 1:length(listSubseq)){
    if(is.subvector(subvec = listSubseq[[i]],vec = A) && is.subvector(subvec = listSubseq[[i]], vec = B)){
      lenACS[length(lenACS)+1] <- length(listSubseq[[i]])
    }
  }

  if(is.null(lenACS)){
    lenACS <- 0
  }

  lenACS
}