Lesson 4.4: List Practice II

Learning Objectives

Students will be able to...

• Traverse a list, accessing each element one at a time
• Perform operations combining all elements in a list
• Select defined subsets of elements in a list

Materials/Preparation

• Lab 4.4 handout (Number Cruncher) (Download in Word) (Link to PDF)

Pacing Guide

Instructor's Notes

• Review
  • Ask students to define "traversal" and outline the basic code pattern
    • You need not write actual code here, but have students mention the key points (index variable, use index to access each item, repeat length of list, etc.)
  • Review solutions to lab 4.3
    • Ask a student to provide their solution to each part
    • Discuss errors or flaws in each solution
    • Point out similarities between each part, emphasizing that the basic code pattern is the same each time with only the operation performed on each item changing
      • If you feel students can handle it, you can further classify various traversals (maps, filters, folds)

                * If necessary, provide the basic code pattern for a traversal again: <br/>
        

        
• Activity
  • Students should complete the "" lab individually
    • The operations in this lab are fairly similar to those in lab 4.3, but work with lists of numbers instead of names. As a result, students should progress more quickly.
    • As in lab 4.3, help students realize that the basic code pattern in each part will be the same.
• Debrief
  • Ask one or two students to share their solution to each part of the lab
    • If all students seem to grasp the concept, not all parts need to be reviewed
    • If skipping some parts, be sure to review at least parts 1.1 (a fold), 2.1 (a map) and 2.2 (a filter)
  • Point out that the solutions from labs 4.3 and 4.4 will look quite similar, even though in lab 4.3 the lists contained names in in lab 4.4 they contained numbers
    • The traversal code pattern is the same regardless of the type of elements in the list

Accommodations/Differentiation

• Advanced students should complete both bonus parts of the lab (1.5 and 2.3) and then assist struggling students.
• Students who need more assistance should focus on parts 1.3, 2.1, and 2.2. Ensure that all students are able to complete at least these three parts before concluding the lesson.