CODEWITHSUNDEEP
java
Citizen0insane00
Citizen0insane00

Reputation: 21

Java indexOf returns -1

So I am reading in a line from a file, that looks like:

Snowman:286:355:10

And this is the first part of the code I wrote to separate the data and place it into arrays. 

 for (int i = 0 ; i<manyItems; i++)
                {
                    a = 0;

                    temp = scan.nextLine();
                    System.out.println(temp);

                    b = temp.indexOf(':');
                    System.out.println(b);

                    items[i] = temp.substring(a,b);
                    System.out.println(items[i]);
                    System.out.println(temp);

                    a = b;

                    System.out.println(temp);

                    b = temp.indexOf(a+1,':');
                    System.out.println(b);

                    rawX[i] = temp.substring(a+1,b);
                    System.out.println(rawX[i]);


                }

It separates "Snowman" places it into the array, however, when I try to find the second colon, indexOf() keeps returning -1. Does anyone know why it is not finding the second colon?

Upvotes: 1

Views: 2241

Answers (4)

Fadi Hanna AL-Kass
Fadi Hanna AL-Kass

Reputation: 629

There's a method under String class that will handle the job for you. Split(regEx pattern) is what you may want to use. The following code will do the job you're trying to perform:

    String input = "Snowman:286:355:10";

    String tokens [] = input.split(":");

    for (int i = 0; i < tokens.length; i++)
        System.out.println(tokens[i]);

Upvotes: 0

sarcan
sarcan

Reputation: 3165

Because you swapped the arguments of the indexOf call. It expects the character, then the index to start looking at. Remember that chars are ints, you're looking for the char 7 starting at the int value of ':'.

Upvotes: 4

Richard JP Le Guen
Richard JP Le Guen

Reputation: 28753

I think you have the arguments backwards:

b = temp.indexOf(a+1,':');

Should be...

b = temp.indexOf(':', a+1);

From docs.oracle.com:

public int indexOf(int ch,
               int fromIndex)

The first argument is the character, the second if the fromIndex.

Upvotes: 4

Thilo
Thilo

Reputation: 262494

You could save all that code and use String#split to split the line:

String[] parts = temp.split(":");

Upvotes: 7

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