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Java programming Exercises: Find and replace a word in a given string

Java Regular Expression: Exercise-13 with Solution

Write a Java program to find the word Python in a given string, if the word Python present in the string return Java otherwise return C++. Ignore case sensitive.

Sample Solution-1:

Java Code:

import java.util.*;

public class test {
 
   public static void main(String[] args) {
	   
	    String text ="python";
		System.out.println("Original string: "+text);
		System.out.println("New string: "+validate(text));
		text ="JavaScript";
		System.out.println("\nOriginal string: "+text);
		System.out.println("New string: "+validate(text));
		text ="PYTHON";
		System.out.println("\nOriginal string: "+text);
		System.out.println("New string: "+validate(text));
        }

   public static String validate(String text) {
	   	String str = text.toLowerCase();
		if (str.contains("python")) {
			return "Java";
		} 
		return "C++";
   }
}

Sample Output:

Original string: python
New string: Java

Original string: JavaScript
New string: C++

Original string: PYTHON
New string: Java

Pictorial Presentation:

Java Regular Expression: Find and replace a word in a given string.
Java Regular Expression: Find and replace a word in a given string.

Flowchart :

Flowchart: Find and replace a word in a given string.

Sample Solution-2:

Java Code:

public class test {
 
   public static void main(String[] args) {
	   
	    String text ="python";
		System.out.println("Original string: "+text);
		System.out.println("New string: "+validate(text));
		text ="JavaScript";
		System.out.println("\nOriginal string: "+text);
		System.out.println("New string: "+validate(text));
		text ="PYTHON";
		System.out.println("\nOriginal string: "+text);
		System.out.println("New string: "+validate(text));
        }

   public static String validate(String text) {
	   return text.matches("(?i).*(?<=python).*") ? "Java" : "C++";
   }
}

Sample Output:

Original string: python
New string: Java

Original string: JavaScript
New string: C++

Original string: PYTHON
New string: Java

Flowchart :

Flowchart: Find and replace a word in a given string.

Java Code Editor:

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Java: Tips of the Day

What is the best way to filter a Java Collection?

Java 8 (2014) solves this problem using streams and lambdas in one line of code:

List<Person> beerDrinkers = persons.stream()
    .filter(p -> p.getAge() > 16).collect(Collectors.toList());

Use Collection#removeIf to modify the collection in place. (Notice: In this case, the predicate will remove objects who satisfy the predicate):

persons.removeIf(p -> p.getAge() <= 16);

lambdaj allows filtering collections without writing loops or inner classes:

List beerDrinkers = select(persons, having(on(Person.class).getAge(),
    greaterThan(16)));

Ref: https://bit.ly/3uwYid6