Convert a string into an int array

Question

I was wondering how would I convert a string to an int array.

I created a reader to read from a text file, which consists of two lines.

The first line is a random quote like "dogs are red"
The second line are numbers.

I am supposed to save each character from the quote into a char array, and then the second line, consisting of the numbers, is the order number of each char, and when printed out in that order, it will spell out a phrase.

I used the .hasNextLine method to first save the two lines into two string variables. Then, I converted the first line into the char array, and that part is ok but I do not know how to convert the second part into an int array.

I called the variable holding the second line "numbers" and it contains the string "6 25 11 32 6 11 44......"

How would I convert this into an int array?

Thanks so much

Wow, you described your intent in plain English :-). It helps when you paste the source code itself. — Kedar Mhaswade
– Kedar Mhaswade, Commented Mar 31, 2016 at 23:19
It'd be helpful if you provided code. That way we'd know where you're stuck. — robotlos
– robotlos, Commented Mar 31, 2016 at 23:19
Taking a leap of faith -- you have a string made of blank separated integers. Each integer is to be read as a "string". Try to separate these number substrings and send them to Integer.valueOf. — Kedar Mhaswade
– Kedar Mhaswade, Commented Mar 31, 2016 at 23:20
Hi, Sorry about that, let me post the code, and yes the numbers are seperated by spaces :). I have to run different files into my program, so everything varies a little bit. — Derek Yee
– Derek Yee, Commented Mar 31, 2016 at 23:35

Magnus · Accepted Answer · 2016-03-31 23:24:49Z

5

You could do something real simple like this:

String[] strArray = input.split(" ");
int[] intArray = new int[strArray.length]; 

for(int i = 0; i < strArray.length; i++) {
    intArray[i] = Integer.parseInt(strArray[i]);
}

Also, you'd want to check for NumberFormatException using a try..catch block.

answered Mar 31, 2016 at 23:24

Magnus

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Comments

robotlos · Accepted Answer · 2016-04-23 01:10:01Z

If your numbers are delimited by spaces like it is described in your post, you can use String.split() to your advantage.

You can create a method like the following which will convert a String of integers to an int[]:

public static int[] stringArrayToIntArray(String intString) {
    String[] intStringSplit = intString.split(" "); //Split by spaces
    int[] result = new int[intStringSplit.length]; //Used to store our ints

    for (int i = 0; i < intStringSplit.length; i++) {
        //parse and store each value into int[] to be returned
        result[i] = Integer.parseInt(intStringSplit[i]); 
    }
    return result;
}

Which can be called like so:

public static void main(String[] args) {

    String intString = "6 25 11 32 6 11 44"; //Original String

    int[] intArray = stringArrayToIntArray(intString); //Call our method

}

If you were to iterate through intArray and print each value with the following:

    for (int i : intArray) {
        System.out.println(i);
    }

You'd get a result of:

run:
6
25
11
32
6
11
44
BUILD SUCCESSFUL (total time: 0 seconds)

Cheers!

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