How to Fill Java Arrays with Ranges of Numbers Like in Perl?

Is there a syntax or package in Java that allows quick filling of arrays with numeric ranges, similar to Perl?

int[] arr = new int[1000];
arr = (1..500, 301..400, 1001..1400); // Expected output [1, 2, 3, 4, ..., 500, 301, 302, ..., 400, 1001, 1002, ..., 1400]

Filling arrays in Java with ranges of numbers can be accomplished through loops or specific libraries. While Java does not directly support range creation syntax like Perl, you can achieve the desired functionality with a few different approaches. Additionally, for efficient access without creating large arrays, there are libraries that can help manage ranges effectively.

import java.util.ArrayList;
import java.util.List;

public class RangeUtil {
    public static int[] fillRanges(String... ranges) {
        List<Integer> resultList = new ArrayList<>();
        for (String range : ranges) {
            String[] parts = range.split("\.\.");
            int start = Integer.parseInt(parts[0]);
            int end = Integer.parseInt(parts[1]);
            for (int i = start; i <= end; i++) {
                resultList.add(i);
            }
        }
        return resultList.stream().mapToInt(i -> i).toArray();
    }
}

// Example usage:
int[] arr = RangeUtil.fillRanges("1..500", "301..400", "1001..1400"); // fills array with specified ranges.

Causes

• Java lacks native syntax for defining ranges like Perl's (1..100).
• Creating large arrays can be memory-intensive and inefficient.

Solutions

• Use a loop to fill the array with desired ranges.
• Consider libraries like Apache Commons Lang or Guava that provide utility methods for creating numeric ranges.
• Create custom classes to manage ranges and allow accessing individual elements without large array creation.

Mistake: Trying to use Perl-style syntax in Java for ranges directly.

Solution: Use a loop or implement a custom function to interpret and create the ranges.

Mistake: Not handling large ranges efficiently, causing memory issues.

Solution: Utilize libraries that allow range management without full array instantiation.