Question

How to find keyword matching between multiple text blocks in Kotlin

Answer 1

/*
    Tokenize text into words.
    - Keeps only letters and digits
    - Splits on punctuation and spaces
*/
fun tokenize(text: String): Set<String> {
    val words: MutableSet<String> = mutableSetOf()
    val sb = StringBuilder()

    for (c in text) {
        if (c.isLetterOrDigit()) {
            sb.append(c.lowercaseChar())
        } else if (sb.isNotEmpty()) {
            words.add(sb.toString())
            sb.clear()
        }
    }

    if (sb.isNotEmpty()) {
        words.add(sb.toString())
    }

    return words
}

/*
    // Find keyword matches across THREE OR MORE texts
    // -------------------------------------------------------------
    This function receives a vector of sets.
    It returns the intersection of ALL sets.
*/
fun findMatchesMultiple(allSets: List<Set<String>>): Set<String> {
    if (allSets.isEmpty()) return emptySet()

    // Start with the first set
    var result: Set<String> = allSets[0].toSet()

    // Intersect with each remaining set
    for (i in 1 until allSets.size) {
        val temp: MutableSet<String> = mutableSetOf()

        for (w in result) {
            if (allSets[i].contains(w)) {
                temp.add(w)
            }
        }

        result = temp
    }

    return result
}

fun main() {

    // -------------------------------------------------------------
    // Three text blocks to compare
    // -------------------------------------------------------------
    val text1 =
        "Machine learning allows computers to learn from data. " +
        "It is widely used in modern applications."

    val text2 =
        "Data science uses machine learning techniques. " +
        "Applications rely on data-driven models."

    val text3 =
        "Modern applications of machine learning include data analysis, " +
        "automation, and intelligent systems."

    // -------------------------------------------------------------
    // Tokenize all texts
    // -------------------------------------------------------------
    val words1 = tokenize(text1)
    val words2 = tokenize(text2)
    val words3 = tokenize(text3)

    // Put them into a vector for multi-text comparison
    val allSets = listOf(words1, words2, words3)

    // -------------------------------------------------------------
    // Find keyword matches across ALL texts
    // -------------------------------------------------------------
    val matches = findMatchesMultiple(allSets)

    // -------------------------------------------------------------
    // Output results
    // -------------------------------------------------------------
    println("Matched Keywords Across ALL Texts:")
    for (w in matches) {
        print("$w ")
    }
}


/*
run:

Matched Keywords Across ALL Texts:
machine learning data applications 

*/

 

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