Groovy - List dropWhile(Closure condition) method

---

---

Description

Groovy List dropWhile(Closure condition) method drops the elements from the list which satisfy the provided condition and returns the remaining items.

Syntax

public List dropWhile(Closure condition)

Parameters

condition − a closure whose evaluation decides the item(s) to be dropped

Return Value

A list of items minus the items from the front of the list which satisfy the condition.

Example - Dropping elements from a List of Integers

Following is an example of the usage of this method −

main.groovy

def lst = [11, 12, 13, 14, 15]

// get remaining items which are less than 13
remainingItems = lst.dropWhile{ it < 13}
println(remainingItems)

// original list is intact
println(lst)

Output

When we run the above program, we will get the following result −

[13, 14, 15]
[11, 12, 13, 14, 15]

Example - Dropping strings from a List of Strings

Following is an example of the usage of this method −

main.groovy

def lst = ["Apple","Mango","Orange","Papaya"]

// get remaining items 
remainingItems = lst.dropWhile{ it.size() == 5}
println(remainingItems)

// original list is intact
println(lst)

Output

When we run the above program, we will get the following result −

[Orange, Papaya]
[Apple, Mango, Orange, Papaya]

Example - Dropping objects from a List of Objects

Following is an example of the usage of this method −

main.groovy

def lst = [new Student(1, "Julie"),new Student(2, "Robert"),new Student(3, "Adam")];

// get remaining items after dropping a student
remainingItems = lst.dropWhile{ it.getRollNo() == 1}
println(remainingItems)

// original list is intact
println(lst)

class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
   
   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

When we run the above program, we will get the following result −

[[ 2, Robert ], [ 3, Adam ]]
[[ 1, Julie ], [ 2, Robert ], [ 3, Adam ]]