How to convert Java Integer to Int Array instance

To convert an Integer or int type data into an int[] array type, you need to do the following steps:

• First, convert your Integer or int into a String
• Then create a new int[] instance and use the value of String.length() method as the size of the array
• Use a for loop to put each String character inside the array

Let’s see an example of converting an int value into an int[].

First, create a String representation of the int type using Integer.toString() method:

public static void main(String[] args)
{
    int num = 12345;
    String temp = Integer.toString(num);
}

Then, create a new int[] where you will put the integers later.

Use the String.length() method to determine the size of the array:

public static void main(String[] args)
{
    int num = 12345;
    String temp = Integer.toString(num);
    int[] numbers = new int[temp.length()];
}

Finally, create a for loop to iterate through the String and assign each character inside the String into the array.

Take a look at the code below:

for (int i = 0; i < temp.length(); i++) {
    numbers[i] =  Character.getNumericValue(temp.charAt(i));
}

You need to use the combination of Character.getNumericalValue() and String.charAt() methods to get the right integer value.

This is because the String.charAt() method returns the number as a String, and you will get the Unicode value of the numbers without using the Character.getNumericalValue() method.

The code below shows the result of calling only the charAt() method:

for (int i = 0; i < temp.length(); i++) {
    numbers[i] =  temp.charAt(i);
}

System.out.println("Variable numbers content: " + Arrays.toString(numbers));
// Variable numbers content: [49, 50, 51, 52, 53]

That’s why you need to wrap the value returned by charAt() method with getNumericalValue() method.

Below is the full code for converting an int to an int[] using Java:

public static void main(String[] args)
{
    int num = 12345;
    String temp = Integer.toString(num);
    int[] numbers = new int[temp.length()];

    for (int i = 0; i < temp.length(); i++) {
        numbers[i] =  Character.getNumericValue(temp.charAt(i));
    }

    System.out.println("Variable numbers type: "
            + numbers.getClass().getSimpleName());
    // Variable numbers type: int[]

    System.out.println("Variable numbers content: "
            + Arrays.toString(numbers));
    // Variable numbers content: [1, 2, 3, 4, 5]
}

Feel free to modify the code above as you require 😉