Java Program to Convert String to Integer Array
Strings – Strings in Java are objects that are supported internally by a char array. Since arrays are immutable, and strings are also a type of exceptional array that holds characters, therefore, strings are immutable as well.
Integer Array – An array is a combination of the same type of variables. Likewise, a collection of integers (int) referred to by a common name is an Integer Array.
Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more, please refer Complete Interview Preparation Course.
Problem Statement – Given a string, the task is to convert that string into an integer array.
Let us first go through few examples to make it more clear.
Examples:
Input : String : "1 23 456 7890" Output : Integer array : [1 23 456 7890]
Input : String : "[1,2,356,678,3378]" Output : Integer array : [1, 2, 356, 678, 3378]
There are numerous approaches to do the same; a few of them are listed below.
Methods:
- Using string.replaceAll() method
- Using string.split() method
Method 1 – Using string.replaceAll() method
The string.replaceAll() method takes two arguments, a regex, and the replacement values. This method will replace the given regex with the given replacement value, and after that, the split() method is used to split the string.
Java
// Java Program to Convert String to Integer Array// Using string.replaceAll() method// Importing input output and utility classesimport java.io.*;import java.util.Arrays;public class GFG { public static void main(String[] args) { // declaring the string String str = "[1,2,356,678,3378]"; // calling replaceAll() method and split() method on // string String[] string = str.replaceAll("\\[", "") .replaceAll("]", "") .split(","); // declaring an array with the size of string int[] arr = new int[string.length]; // parsing the String argument as a signed decimal // integer object and storing that integer into the // array for (int i = 0; i < string.length; i++) { arr[i] = Integer.valueOf(string[i]); } // printing string System.out.print("String : " + str); // printing the Integer array System.out.print("\nInteger array : " + Arrays.toString(arr)); }} |
String : [1,2,356,678,3378] Integer array : [1, 2, 356, 678, 3378]
Method 2 – Using string.split() method
The string.split() method is used to split the string into various sub-strings. Then, those sub-strings are converted to an integer using the Integer.parseInt() method and store that value integer value to the Integer array.
Java
// Java Program to Convert String to Integer Array// Using string.split() method// Importing input output and utility classesimport java.io.*;public class GFG { // Function for conversion static int[] method(String str) { String[] splitArray = str.split(" "); int[] array = new int[splitArray.length]; // parsing the String argument as a signed decimal // integer object and storing that integer into the // array for (int i = 0; i < splitArray.length; i++) { array[i] = Integer.parseInt(splitArray[i]); } return array; } // main method public static void main(String[] args) { // Bufferedreader declaration BufferedReader br = new BufferedReader( new InputStreamReader(System.in)); // string declaration String str = "1 23 456 7890"; int i; // declaring the variable & calling the method with // passing string as an argument int[] array = method(str); // printing the string System.out.print("\nString : " + str); // printing the Integer array System.out.print("\nInteger array : ["); for (i = 0; i < array.length; i++) { System.out.print(array[i] + " "); } System.out.print("]"); }} |
String : 1 23 456 7890 Integer array : [1 23 456 7890 ]
