Java ArrayList removeIf() Method
Java ArrayListThe removeIf() method is used to remove all array elements that satisfy a specific condition.
The syntax of the removeIf() method is:
arraylist.removeIf(Predicate<E> filter)
Note:arraylist is an object of the ArrayList class.
Parameter Description:
- filter - A filter that determines whether an element should be removed.
Return Value
Returns true if an element is removed.
Example
The following example demonstrates the use of the removeIf() method:
Example
class Main {
public static void main(String[] args){
// Create a dynamic array
ArrayList<String> sites = new ArrayList<>();
sites.add("Google");
sites.add("Example");
sites.add("Taobao");
System.out.println("ArrayList : " + sites);
// Remove elements whose name contains Tao
sites.removeIf(e -> e.contains("Tao"));;
System.out.println("ArrayList after removal: " + sites);
}
}
The output of the above program is:
ArrayList : [Google, Example, Taobao] 删除后的 ArrayList: [Google, Example]
In the above example, we usedJava String contains() methodto check whether the element contains "Tao".
e -> e.contains("land")Returns true if the element contains "land".
removeIf()Ife -> e.contains("land")returns true, the element is removed.
Remove even elements:
Example
class Main {
public static void main(String[] args) {
// Create an array
ArrayList<Integer> numbers = new ArrayList<>();
// Insert elements into the array
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(4);
numbers.add(5);
numbers.add(6);
System.out.println("Numbers: " + numbers);
// Remove all even elements
numbers.removeIf(e -> (e % 2) == 0);;
System.out.println("Odd Numbers: " + numbers);
}
}
The output of the above program is:
Numbers: [1, 2, 3, 4, 5, 6] Odd Numbers: [1, 3, 5]
In the above example, we created a dynamic array named numbers.
Note the expression:
numbers.removeIf(e -> (e % 2) == 0);
e -> (e % 2) == 0)is a lambda expression (anonymous function). It checks whether an element is divisible by 2.
To learn more about anonymous functions, visitJava Lambda Expressions。
removeIf()If the methode -> (e % 2) == 0returns true, then the element is removed.
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