Java Collection removeIf() Method with Examples

by Online Tutorials Library July 22, 2022

Java Collection removeIf() Method

The removeIf() method of Java Collection Interface removes the elements of this queue that satisfies the given predicate filter.

Syntax

Parameters

The parameter ‘filter’ represents a predicate which returns true for the elements to be removed.

Return Value:

The removeIf () method returns a Boolean value ‘true’ if the collection has removed any element, else it returns ‘false’.

Throws

UnsupportedOperationException– if the elements cannot be removed from this collection.

NullPointerException– if the specified filter is null.

Example 1

  import java.util.Collection;  import java.util.concurrent.ConcurrentLinkedQueue;  import java.util.function.Predicate;  public class JavaCollectionRemoveIfExample1 {      public static void main(String[] args) {          Collection<Integer> collection = new ConcurrentLinkedQueue<Integer>();          for (int i=1;i<21;i++){              collection.add(i);}          System.out.println(“Total no : “+ collection);          //removes all the elements which satisfies the predicate filter          Predicate<Integer> pr= a->(a%2!=0);          //remove all the elements which do not come in 2’s table          collection.removeIf(pr );          System.out.println(” Table of 2 = “+collection);      }  }  

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Output:

Total no : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]   Table of 2 = [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]

Example 2

  import java.util.Collection;  import java.util.concurrent.ConcurrentLinkedQueue;  import java.util.function.Predicate;  public class JavaCollectionRemoveIfExample2 {      static int i=1;      public static void main(String[] args) {          Collection<IsPass> collection = new ConcurrentLinkedQueue<IsPass>();          IsPass isVoter1 = new IsPass(“Reema”,98);          IsPass isVoter2 = new IsPass(“Raj”,71);          IsPass isVoter3 = new IsPass(“Kajol”,37);          IsPass isVoter4 = new IsPass(“Ravi”,47);          IsPass isVoter5 = new IsPass(“Varun”,17);          collection.add(isVoter1);          collection.add(isVoter2);          collection.add(isVoter3);          collection.add(isVoter4);          collection.add(isVoter5);          //removes all the elements which satisfies the Predicate filter          Predicate<IsPass> pr= (IsPass marks) ->(marks.marks < 45);          collection.removeIf(pr );          System.out.println(” People who passed the exam : “);          for (IsPass xyz : collection ){              System.out.println(i++ +”. “+xyz);          }      }  }  class IsPass {      String name;      int marks;      public IsPass(String name, int age) {          this.name = name;          this.marks = age;      }      public String toString() {          return this.name + ”  has passed the exam with ” + this.marks +” marks.”;      }  }  

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Output:

People who passed the exam :   1. Reema  has passed the exam with 98 marks.  2. Raj  has passed the exam with 71 marks.  3. Ravi  has passed the exam with 47 marks.

Example 3

  import java.util.Collection;  import java.util.concurrent.ConcurrentLinkedQueue;  import java.util.function.Predicate;  public class JavaCollectionRemoveIfExample3 {      public static void main(String[] args) {          Collection<Character> collection = new ConcurrentLinkedQueue<Character>();          char c;          for(c=’A’;c<=’Z’;++c){              collection.add(c);          }          System.out.println(“Albabets : “+ collection);          //removes all the elements which satisfies the predicate filter          Predicate<Character> pr= a->(a!=’A’&& a!=’E’&& a!=’I’&& a!=’O’&& a!=’U’ );          //remove all the non vowels alphabets          collection.removeIf(pr );          System.out.println(” Vowels = “+collection);      }  }  

Test it Now

Output:

Albabets : [A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z]   Vowels = [A, E, I, O, U]

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Java Collection removeIf() Method with Examples

Java Collection removeIf() Method

Syntax

Parameters

Return Value:

Throws

Example 1

Example 2

Example 3

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