Performing a search in String[][]

Question

Give a two-dimensional array T with base type String and some string str (which can be treated like an array of type String) I want to check if T contains certain parts str as its entries. I tried this:

int indeksck = str.indexOf("C");

while(k<T.length){
    if(T[k][2] == str.substring(indeksck+1)){
        if(T[k][1] == str.substring(6, indeksck)){
            int ile_o = Integer.parseInt(T[k][0]);
            T[k][0]= Integer.toString(ile_o+1);
            T[k][3] = T[k][3]+"X"+str.substring(1,6);
            k = T.length+1;
        } else {
            k++;
        }

    } else {
        k++;

        if(k==T.length){
            k = 0;
            while(k<T.length){
                if(T[k][0]==null){
                    T[k][0] = Integer.toString(1);
                    T[k][1] = str.substring(6,indeksck);
                    T[k][2] = str.substring(indeksck+1);
                    T[k][3] = str.substring(1,6);
                    k = T.length+1;
                } else {
                    k++;
                }
            }
        }
    }
}

The problem is that the first part of my code is being ignored (even when condition should be satisfied). I would appreciate and suggestions on solving this problem.

never compare strings with `==`, use `.equals()`, [read this](http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) for an explanation. — jlordo, Dec 29 '12 at 14:26
There's a lot going on here that you aren't explaining. Why start at substring index `6`? Why does every entry `T[k]` only have indices `0-3`? What's the `X` about? Why are you incrementing `T[k][0]` by 1 and converting back to string? Can you provide an example of the contents of `T` and `str`, and what exactly your code is looking for? — mellamokb, Dec 29 '12 at 14:27
@mellamokb The string is formatted is special way, I don't think it's important. — borg, Dec 29 '12 at 14:29
if `equals()` returns `false` for two strings, than they don't have the same exact content. — jlordo, Dec 29 '12 at 14:30
It appears you are using arrays when you should be using objects (or a collection of objects) — Peter Lawrey, Dec 29 '12 at 14:33
@PeterLawrey Do you mean I should use Object[][] instead of String[][]? — borg, Dec 29 '12 at 14:34
I mean you should use `List` where MyType has fields with approriate types. This would make the purpose of each "column" clear and remove the need to convert between `int` and `String` — Peter Lawrey, Dec 29 '12 at 14:37

score 6 · Accepted Answer · answered Dec 29 '12 at 14:28

6

You cannot use == to do string compare. Try:

if(T[k][2].equals(str.substring(indeksck+1))) {

answered Dec 29 '12 at 14:28

TieDad

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score 2 · Answer 2 · answered Dec 29 '12 at 14:32

2

== operator in Java is used for reference comparison. To check equivalence for objects (so also for strings) you need to use equals() method.

answered Dec 29 '12 at 14:32

davioooh

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Performing a search in String[][]

2 Answers2