Convert String to Array of Integers in Java: Multiple Approaches

Converting a string representation of an array into an actual array of integers is a common task in programming, particularly in Java. This article explores multiple methods to transform a string like [123455] into an array [1 2 3 4 5 5] in Java. We will start with a straightforward approach and then dive into more advanced techniques using Java Streams and JSON parsing.

Step-By-Step Conversion: Basics

Here is a detailed explanation of the step-by-step process to convert a string to an array of integers in Java:

Remove the brackets: Trim the opening and closing brackets from the string. Split the string: Divide the string into individual number strings by splitting it at commas or spaces. Convert to integers: Convert each number string to an integer after removing any extra whitespace. Store in an array: Create an integer array and store the converted values.

Java Code Example

Below is a sample Java code that implements the above steps:

import ;
public class StringToArray {
    public static void main(String[] args) {
        String str  "[123455]";
        // Step 1: Remove the brackets
        str  (1, str.length - 1);
        // Step 2: Split the string by commas
        String[] stringArray  str.split(",");
        // Step 3: Convert the string array to an integer array
        int[] intArray  new int[stringArray.length];
        for (int i  0; i  stringArray.length; i   1) {
            intArray[i]  (stringArray[i].trim());
        }
        // Output the resulting array
        (intArray).forEach((element)(element));
    }
}

Moderate Method: Using Java Streams

A more concise way to achieve the same result is by using Java Streams. Here's an example of how to convert the string to an array of integers using streams:

Java Code Example with Streams

import ;
public class StringToArrayWithStreams extends StringToArray {
    public static void main(String[] args) {
        String str  "[123455]";
        final int[] intArray  (1,str.length - 1)
                .chars()
                .filter((ch)-((ch))
                .map((ch)(()))
                .toArray();
        (intArray).forEach((element)(element));
    }
}

Advanced Method: Using JSON Libraries

Another interesting way to convert the string to an array of integers is by parsing it as a JSON array. This method is especially useful if the string is formatted as a valid JSON array. Here's how you can do it:

Java Code Example with JSON Parsing

import ;
public class StringToArrayWithJson extends StringToArray {
    public static void main(String[] args) {
        String str  "[123455]";
        int[] intArray  ().fromJson(str, new int[][].class[0].getClass());
        (intArray).forEach((element)(element));
    }
}

Conclusion

Converting a string representation of an array into an actual array of integers is a task that can be accomplished in multiple ways. This article has showcased three different methods: a step-by-step approach, using Java Streams, and parsing as JSON. Each method has its own merits, and the choice of method depends on the specific requirements and the context in which the conversion is needed. Whether you are a beginner or an experienced developer, understanding these methods can enhance your skills and provide versatile solutions for similar tasks.