Convert Integer List to int array

Question

Is there a way, to convert a List of Integers to Array of ints (not integer). Something like List to int []? Without looping through the list and manually converting the intger to int.

Answer 1

You can use the toArray to get an array of Integers, ArrayUtils from the apache commons to convert it to an int[].

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List<Integer> integerList = new ArrayList<Integer>();
Integer[] integerArray = integerList.toArray(new Integer[0]);
int[] intArray = ArrayUtils.toPrimitive(integerArray);

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Resources :

• Apache commons - ArrayUtils.toPrimitive(Integer[])
• Apache commons lang
• Javadoc - Collection.toArray(T[])

On the same topic :

• How to convert List to int[] in Java?