Drop ‘where’ and move the condition into the ‘firstordefault’.

To drop the ‘where’ clause and move the condition into the ‘FirstOrDefault’ method, you can rewrite the code as follows:

Example scenario: Assume you have a list of students and you want to find the first student whose age is greater than 18.

      List<Student> students = new List<Student>()
      {
          new Student { Name = "John", Age = 20 },
          new Student { Name = "Sarah", Age = 19 },
          new Student { Name = "Mike", Age = 22 }
      };

      Student firstStudentWithAgeGreaterThan18 = students.FirstOrDefault(s => s.Age > 18);
    

In the above example, we have a list of students where the condition for finding the first student with an age greater than 18 is moved to the ‘FirstOrDefault’ method. The lambda expression ‘s => s.Age > 18’ is now directly passed to the method.

This code will find the first student from the ‘students’ list whose age is greater than 18 and assign it to the ‘firstStudentWithAgeGreaterThan18’ variable. If no such student is found, the variable will be assigned null.

By dropping the ‘where’ clause and moving the condition into the ‘FirstOrDefault’ method, we eliminate the need to explicitly mention the ‘where’ keyword and simplify the code.

Please note that the above code is written in C#.