Trying to figure out how many times a certain set of characters appears in a bigger one with copying Arrays. Getting an error + is this the best way?

Question

I want to write a program that figures out how many times a certain set of characters repeats itself in a longer set of characters (several times for several different set of characters)

I tried to achieve this by "importing" the long set of characters into a char array, and then make a 2D array for all the shorter sets of characters that I want to check the occurence of.

Then, I wanted my for loop to create an "interim" array of the same length as the short arrays have and compare it to each of them, however, the program keeps returning 0 occurences no matte what... And is also taking too long to compute when checking longer arrays with loads of character sets.

import java.util.*;
public class A {

public static void main (String [] args) {
    Scanner sc = new Scanner (System.in);

    //Preberi podatke
    int dolzinaDolgi = sc.nextInt(); //D
    int dolzinaKratki = sc.nextInt(); //d
    int stKratkih = sc.nextInt(); //n
    sc.nextLine(); // prehod v novo vrstico
    char [] Dolgi = sc.nextLine().toCharArray(); //prebrano dolgo zaporedje
    char [][] TabelaKratki = new char [stKratkih][dolzinaKratki];
    int [] results = new int [stKratkih];
    for (int i=0; i<stKratkih; i++) {
        TabelaKratki[i]=sc.nextLine().toCharArray();
    }
    for (int i=0; i<dolzinaDolgi-dolzinaKratki; i++) {
        char [] vmesnoZaporedje = new char [dolzinaKratki];
        vmesnoZaporedje = Arrays.copyOfRange (Dolgi, 0+i, dolzinaKratki+i-1);
        for (int j=0; j<stKratkih; j++) {
            if (TabelaKratki [j] == vmesnoZaporedje) {
                results [j] += 1;
            }
        }
    }
    for (int index = 0; index<stKratkih; index++) {
        System.out.println(results[index]);
    }

}

}

Possible duplicate of [Best way to copy from one array to another](http://stackoverflow.com/questions/6537589/best-way-to-copy-from-one-array-to-another) — OneCricketeer, Dec 10 '16 at 17:21
Specifically, the Arrays.copy method, not the accepted answer — OneCricketeer, Dec 10 '16 at 17:22

score 1 · Answer 1 · edited May 23 '17 at 12:13

1

Perhaps regular expression is much better. 1. Convert the text to be searched into a pattern. 2. Store all different sets of characters into array. 3. Loop the array and loop to find occurrences using the pattern.

Refer to this answer for count the occurrences. java regex match count

edited May 23 '17 at 12:13

Community

1
1

answered Dec 10 '16 at 18:52

Azman K.

11
1

Please show a small example of how this can be done for a part of the text – ItamarG3 Dec 10 '16 at 19:14
Thank you, but as this is a homework assignment, I'd much raher work with arrays - as this is what we are using now. – Vid Stropnik Dec 10 '16 at 19:53

Trying to figure out how many times a certain set of characters appears in a bigger one with copying Arrays. Getting an error + is this the best way?

1 Answers1