Java 8 | ArrayDeque removeIf() method in Java with Examples
Last Updated :
10 Dec, 2018
The removeIf() method of ArrayDeque is used to remove all those elements from ArrayDeque which satisfies a given predicate filter condition passed as a parameter to the method. This method returns true if some element are removed from the Vector.
Java 8 has an important in-built functional interface which is Predicate. Predicate, or a condition checking function, which checks the given input for a given condition and returns a boolean result for the same indicating whether the condition was met or not.
Syntax:
public boolean removeIf(Predicate<? super E> filter)
Parameter: This method takes a parameter filter which represents a predicate which returns true for elements to be removed.
Returns: This method returns True if predicate returns true and some elements were removed.
Exception: This method throws NullPointerException if the specified filter is null.
Below programs illustrate removeIf() method of ArrayDeque:
Example 1: To demonstrate removeIf() method on ArrayDeque which contains a set of String and remove strings starts with A.
import java.util.*;
public class GFG {
public static void main(String[] args)
{
ArrayDeque<String> students = new ArrayDeque<String>();
students.add("Aman");
students.add("Sanjeet");
students.add("Amar");
students.add("Rabi");
students.add("Shabbir");
students.removeIf(n -> (n.charAt(0) == 'A'));
System.out.println("Students name do not starts with A");
for (String str : students) {
System.out.println(str);
}
}
}
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Output:
Students name do not starts with A
Sanjeet
Rabi
Shabbir
Example 2: To demonstrate removeIf() method on ArrayDeque which contains set of Students objects to remove all those students who got less than 40 marks.
import java.util.*;
public class GFG {
public static void main(String[] args)
{
ArrayDeque<student> students = new ArrayDeque<student>();
students.add(new student("Aman", 78));
students.add(new student("Amar", 79));
students.add(new student("Suraj", 38));
students.add(new student("Raju", 22));
students.add(new student("Ankit", 76));
students.add(new student("Sanju", 62));
students.removeIf(n -> (n.marks <= 40));
System.out.println("Students list who score above 40");
for (student str : students) {
System.out.println(str.name + ", " + str.marks);
}
}
}
class student {
public String name;
public int marks;
student(String name, int marks)
{
this.name = name;
this.marks = marks;
}
}
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Output:
Students list who score above 40
Aman, 78
Amar, 79
Ankit, 76
Sanju, 62
Example 3: To demonstrate NullpointerException in removeIf() method.
import java.util.*;
public class GFG {
public static void main(String[] args)
{
ArrayDeque<String> students = new ArrayDeque<String>();
students.add("Aman");
students.add("Sanjeet");
students.add("Amar");
students.add("Rabi");
students.add("Shabbir");
try {
students.removeIf(null);
}
catch (Exception e) {
System.out.println("Exception: " + e);
}
}
}
|
Output:
Exception: java.lang.NullPointerException
Reference: https://docs.oracle.com/javase/10/docs/api/java/util/ArrayDeque.html#removeIf(java.util.function.Predicate)
