[R] Checking for combination of words in a sentence

[vioravis]

I am trying to implement some expert rules based on the presence or absence
of words in a sentence. I have given a reproducible example below. In this,
every time I come across the words lunch and bag in the same sentence, the
outcome would be 1. If lunch and pack are in the same sentence, then the
outcome would be 2. If only lunch is present, the outcome would be 3. There
is no guarantee that these two words (lunch/bag or lunch/pack) will be next
to each other in the sentence. I tried to implement this using regexpr but
the last rule (lunch -> 3) supersedes the other two rules. This works fine
only if I have lunch only as the first rule following by the other two. 

Is there a way to make sure outcome will be 3 if only lunch is present? (I
have hundreds of rules; Hence, finding out the correct order manually is not
possible(



keyWord <- c("lunch bag","lunch pack","lunch")
outcome <- c(1,2,3)

expertRules<- data.frame(keyWord = keyWord, outcome = outcome)


testWords <- c("lunch pack","lunch","lunch","lunch bag","lunch pack")
predictedOutcome <- c(NA,NA,NA,NA,NA)

testDf <- data.frame(testWords = testWords, 
                     predictedOutcome = predictedOutcome)

for(i in 1:nrow(expertRules))
{

  testDf$predictedOutcome <-
ifelse((regexpr(expertRules[i,1],testDf$testWords)>0),
                                     expertRules[i,2],
                                     testDf$predictedOutcome)
}


> testDf
   testWords predictedOutcome
1 lunch pack                3
2      lunch                3
3      lunch                3
4  lunch bag                3
5 lunch pack                3



Thank you.

Ravi

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