1.5

1. Exam Points

• Traverse one list or two lists
• Manipulate list elements using various procedures, including INSERT, APPEND, REMOVE, LENGTH, etc.

2. Knowledge Points

(1) Lists

• A list is an ordered sequence of elements.
• A value in the list is called an element.
• An index is a common method for referencing the elements in a list or string using natural numbers (1,2,3,…).
• The starting index of a list is 1. (!!!)

(2) Manipulate Lists

• A. Create a list

  • 
  • Remember to use ”” to enclose string values.
  • Assign one list to another means copying the values of one list to the other.

• B. Access an element by index: listName[index]

  • aList[2] = 10
  • bList[1] = "Annabelle"
  • DISPLAY(cList[3])

• C. Assign a value of an element of a list to a variable

  • x ← aList [3]

• D. Assign a value to an element of a list

  • aList [4] ← x

• E. Insert an element at a given index: INSERT(listName, index, value)

  • INSERT (aList, 3, 100)

• F. Add an element to the end of a list: APPEND(listName, value)

  • APPEND (aList, 66)

• **G. Remove elements: REMOVE(listName, index) **

  • REMOVE (aList, 3)

• **H. Determine the length of a list: LENGTH(listName) **

  • LENGTH (aList)

• I. Traverse a list
  

  • Syntax:
    
  • The variable item is the current element traversed.
  • Example 1: Compute the sum of all the elements in a list
    
  • Example 2: Find the maximum element
    

• Linear search or sequential search algorithms check each element of a list, in order, until the desired value is found or all elements in the list have been checked.

(3) For FRQs

• Benefits of using lists:
  • Elements in a list can be manipulated in a unified approach, that means you can apply the same operation on the elements by accessing them using indexes.
  • With a list, you do not need to store elements with different variables, which reduces complexity.

3. Exercises

• Practice
• Solution