CODEWITHSUNDEEP
carduinosubstringindexof
Mathlight
Mathlight

Reputation: 6653

indexOf and substring skipping 1 result

I'm trying to separate / explode an String to do something with it later on.

The input string is this:

1_2_3_2_2

The function I'm calling with the above value as parameter:

void parseXString(String value){
  int amountX = (value.length() / 2) + 1;
  int seperatorIndex = value.indexOf('_');
  int secondSeperator = 0;

  for(int i = 0; i < amountX; i++){
    String xPoint = "";

    if(i == 0){
      xPoint = value.substring(0, seperatorIndex);
    }else{
      xPoint = value.substring(seperatorIndex + 1, secondSeperator);
    }

    sendMessage((String)i + " X = " + xPoint + " || SEP: " + (String)seperatorIndex + " / " + (String)secondSeperator );

    seperatorIndex = value.indexOf("_", seperatorIndex + 1);
    secondSeperator = value.indexOf("_", seperatorIndex + 1);


  }

  sendMessage("Last X = " + value.substring(seperatorIndex + 1));
}

The sendMessage function will shout the value back to the operating Java application. The output I get is this:

0 X = 1 || SEP: 1 / 0
1 X = 3 || SEP: 3 / 5
2 X = 2 || SEP: 5 / 7
3 X = 2 || SEP: 7 / -1
4 X = 1 || SEP: -1 / 1
Last X = 2_3_2_2

As you can notice, on the second iteration there should be an return of the value 2 instead of an 3.

I think there's something wrong with the seperatorIndexes, but I'm out of the blank right now (working on this way to long).

So my question is very simple. Why doesn't I get the right value back / how can I fix that?

Upvotes: 1

Views: 169

Answers (1)

greyhairredbear
greyhairredbear

Reputation: 802

Your error is that you increase seperatorIndex in the first iteration. Therefore, seperatorIndex is 3 in your second iteration.

You should put the part where you increment seperatorIndex into the else part of your if(i == 0) condition. When doing this, you also have to increment secondSeperator in the if part of your condition.

Upvotes: 2

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