Hello folks,
In this post, we will learn how to replace a sub string in a given string. Detailed description of problem is given below:
Problem:
You have an input string and you need to replace sub string from new sub string in given input string.
Example:
Input: This bike is my bike.
Action: Replace “bike” from “car.
output: This car is my car.
Logic:
- We will use split method and will split given input string from word which needs to be replaced. Remember, how split works.
- After split, add new word at end of all split word except last one.
- First verify if last word in input string is equal to string to be replaced. If yes then append new word.
Solution:
package MakeSeleniumEasy;
import java.util.Scanner;
public class ReplaceString
{
public static void main(String[] args)
{
Scanner sc= new Scanner(System.in);
System.out.println("Enter string:");
String inputString= sc.nextLine();
System.out.println("Enter word to be replaced from:");
String from= sc.nextLine();
System.out.println("Enter word to replaced to:");
String to= sc.nextLine();
System.out.println("Input string: "+inputString);
System.out.println("Word to be replaced from: "+from);
System.out.println("Word to be replaced to: "+to);
String replacedString = replaceMethod(inputString, from, to);
System.out.println(replacedString);
}
static String replaceMethod(String str, String from, String to)
{
// We will split string array using wordToBeReplaced. Splitter word will not be stored.
String[] arr = str.split(from);
StringBuilder output = new StringBuilder();
//Concatenating new word in last of word of each index except last index
// We can not add new word for last indexed word as we are not sure we need to add or not.
int i = 0;
for (; i < arr.length - 1; i++)
{
output.append(arr[i]).append(to);
}
output.append(arr[i]);
// Verifying if last word of given string is similar to word to be replaced/
// If yes, then append new word otherwise don't.
if(str.substring((str.length()-from.length()),str.length()).equals(from))
{
output.append(to);
}
return output.toString();
}
}
Output:
Enter string: this car is my car Enter word to be replaced from: car Enter word to replaced to: bike Input string: this car is my car Word to be replaced from: car Word to be replaced to: bike this bike is my bike ============================ Enter string: thiscarismycar Enter word to be replaced from: car Enter word to replaced to: bike Input string: thiscarismycar Word to be replaced from: car Word to be replaced to: bike thisbikeismybike
I have put comments wherever it is necessary. If you have any doubt, you can ask me.
#HappyCoding
public class ReplaceAllDemo {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println(“Enter string:”);
String inputString = sc.nextLine();
System.out.println(“Enter word to be replaced from:”);
String from = sc.nextLine();
System.out.println(“Enter word to replaced to:”);
String to = sc.nextLine();
System.out.println(“Input string: ” + inputString);
System.out.println(“Word to be replaced from: ” + from);
System.out.println(“Word to be replaced to: ” + to);
inputString = inputString.replaceAll(from, to);
System.out.println(inputString);
}
}
Hi Shreyansh,
In interviews, mostly it is asked to di without using any methods.