How to check if a string is made up entirely of certain string patterns

Question

I have a vector of strings which I need to check to see if they fit a certain criteria. For example, if a certain string, say "34|40|65" is made up entirely of these patterns: c("34", "35", "37", "48", "65"), then I want to return 1, if they string does not contain any of these patterns, then I want to return -1. If the string contains some patterns, but is not totally made up of these patterns, then I want to return 0. I have successfully achieved 1 and -1, but am having trouble with the logic which would yield 0. As stands, my logic yields 1 for those strings which should yield 0. Here is my code to determine if the string contains one of these patterns. This would give me the 1s.

acds <- c("34", "35", "37", "48", "65")
grepl(paste(acds, collapse = "|"), data$comp_cd)

data$comp_cd is the vector of strings

Thanks!

Answer 1

You can check the matches with:

sapply(strsplit(string,"\\|"), function(x) x %in% patterns)

You can easily wrap this in a function to give the numerical result as requested.

checkstring <-function(string,patterns)
{
  matches = sapply(strsplit(string,"\\|"), function(x) x %in% patterns)
  if(sum(matches)==length(matches))
    return(1)
  if(sum(matches)==0)
    return(-1)
  else
    return(0)
}

Example of usage:

checkstring("34a|65a",patterns=patterns)
[1] -1
checkstring("34|65",patterns=patterns)
[1] 1
checkstring("34|40|65",patterns=patterns)
[1] 0

Hope this helps!