CODEWITHSUNDEEP
java
yiwei
yiwei

Reputation: 4180

Comparing two String arrays

I'm making a program that compares two text files and returns their similarity (based on a given algorithm). For each unique word in the first file, I want to find the probabilities that they occur in the second file. But whenever I run my program the similarity returned is always 0.0. This is what I have right now:

public static double nestedLoop(String[] doc1, String[] doc2) {
    // nested loop: sort doc1, for each unique word in doc1, find all
    // occurences in doc2 using a sequential search

    java.util.Arrays.sort(doc1);

    double similarity = 0.0;

    for (int i = 0; i < doc1.length - 1; i++) {
        if (doc1[i] != doc1[i + 1]) {
        String unique = doc1[i];
        double count = 0.0;
            for (int j = 0; j < doc2.length; j++) {
                if (unique == doc2[j]) {
                    count++;
                    similarity += count / doc2.length;
                }
            }
        }
    }
    return similarity;
}

Can someone tell me what is going on?

Upvotes: 1

Views: 3056

Answers (1)

kosa
kosa

Reputation: 66637

if (unique == doc2[j]) {

should be

if (unique.equals(doc2[j])) {

Same for if (doc1[i] != doc1[i + 1]) {

should be:

 if (!(doc1[i].equals(doc1[i + 1]))) {

String comparison should always use equals() instead of == (except case of String literal comparison)

Please read How do I compare strings in Java?

Upvotes: 9

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