Convert string array to int array (generics?)

Question

I have a string that I want to split with a certain delimiter

private int [] mMaxValues;

    public void setMaximum(String maximum) {
       mMaxValues = splitByDelimiter(maximum, ":");
    }

But the splitByDelimiter method return a string array into an int array

public String[] splitByDelimiter(String list,String delimiter) {
    String[] items = list.split("\\" + delimiter);

    for (String s : items) {
        s.trim();
    }

    return items;
}

What is the best way to fix this problem? I'm guessing that iterating the string array and casting them to integers isn't the best solution.

I could also create a new splitByDelimiter that returns an int array but I'm guessing there is a better solution than that..

Is this a situation where you could use generics (I don't have a lot of experience with generics)?

Thx :)

You can't cast a String to an int, you need to parse it and there is no way to do this automagically. — Peter Lawrey
– Peter Lawrey, Commented Sep 7, 2012 at 9:29
I guess your returned String[] only contains Strings that can be parsed to an Integer? In other words it contains numbers as Strings?! — Fabian Barney
– Fabian Barney, Commented Sep 7, 2012 at 9:31
Your for loop isn't doing anything. Strings are immutable, so you're trimming the copy of the strings in array. — nullpotent
– nullpotent, Commented Sep 7, 2012 at 9:33
No, it can also contain Strings that can't be converted to Integers. I use to split any string with a given delimiter a return an array. — Robby Smet
– Robby Smet, Commented Sep 7, 2012 at 9:34
So what should be done with the Strings in the returned String[] that cannot be parsed to an Integer? Do you simply want to ignore them? It's always useful to provide some sample input and the expected output. Input: "bla:123:456:blub:789", Output: {123,456,789} or something like that ... — Fabian Barney
– Fabian Barney, Commented Sep 7, 2012 at 9:35

Nandkumar Tekale · Accepted Answer · 2012-09-07 09:41:27Z

3

You need to convert string array to int array explicitly. Use:

public void setMaximum(String maximum) {
   Strin[] array = splitByDelimiter(maximum, ":");
   int i = 0;
   mMaxValues = new int[array.length];
   for (String value : array) {
       mMaxValues[i] = Integer.parseInt(value);
       i++;
   }
}

Also you need to handle few cases which may cause NullPointerException :

maximum is null
array is null
NumberFormatException may be raised while parsing Integer.parseInt(value), handle it.

edited Sep 7, 2012 at 9:41

answered Sep 7, 2012 at 9:33

Nandkumar Tekale

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Comments

Wouter Lievens · Accepted Answer · 2012-09-07 09:29:53Z

1

Loop over the string array and store them in an int array.

String input = ...;
String[] parts = input.split(':');
int[] result = new int[parts.length];
for (int n = 0; n < parts.length; ++n)
{
  result[n] = Integer.parseInt(parts[n]);
}
return result

answered Sep 7, 2012 at 9:29

Wouter Lievens

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4 Comments

Peter Lawrey Over a year ago

It appears he want to trim() each of the parts before parsing them.

Wouter Lievens Over a year ago

That's a trivial change: parts[n].trim()

Baz Over a year ago

@iccthedral No it won't. Try Integer.parseInt(" 8 "). Gives a NumberFormatException.

Fabian Barney Over a year ago

@iccthedral No, it does not. It throws NumberFormatException in such cases.

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