A list is a group of mutable memory locations that can contain elements of different types. Each element has a position number called a subscript or index starting from 0. Lists are initialized using listName = [ele1, ele2, ...] syntax. Traversing a list with a for loop allows updating, mathematical operations, printing, searching, and testing on all elements easily regardless of the list's size. Common list functions include declaring empty lists, appending elements, and other functions.

1. Lists

2. List
• A list is a consecutive group of mutable memory locations.
• Each element can be a different type
• Each individual value in an list is referred to as an element.
• The position number is more formally called a subscript or index.
• Subscripts must be an integer
• Can use an expression as an index.
• The first element in every kist has subscript 0 (zero) and is sometimes called the
zeroth element.
• To refer to a particular location or element in the list, specify the name of the list
and the index of the particular element.
• The size of an list is how many elements in the list, denoted by n.

4. Checkpoint:
• 1. What is the size of an array?
• 2. What is the range of indices of an array?
Refer to the following array:
int age[] = {10, 11, 18, 13, 13, 16, 41, 12};
• 3. What is in the 7th
position in the array?
• 4. What element is storing the value 12?

5. List Initializer
• To create and initialize a list is similar to a variable
declaration only with multiple elements instead od a
single one:
 Co d e : l i s t Na me = [ e l e 1 , e l e 2 , … ]
 Ex .
▫ na me s = [ “ Fr a nke ns t e i n” , We r e wo l f ” ,
“ Bo o g e y ma n” ]
▫ a g e s = [ 1 8 , 1 8 , 2 1 , 2 1 , 2 1 , 2 2 , 3 5 , 3 8 , 3 2 ,
3 6 ]
▫ Co mbo = [ 2 3 , “ Ca ke ” , “ Cup c a ke s ” , 3 4]

6. Traversing an Array
• In order to access each element of an array we must
hard code each statement which can take up lots of
code.
• Also if we are trying to program in the general if we
add an extra element we have to change all of our
code
▫ Question: How could we traverse or iterate through

7. VS

8. Reasons traversing an array with a for loop
helps with programming in the general
• Updating
• Mathematical operations ( ie. Summing)
• Printing
• Searching
• Testing

9. Common List Functions

10. Declaring Lists
 Lists are dynamic data structures
 To declare a list when not initializing:
○ Code: listNa me = []
 The interpreter reserves memory as it is needed.
 In order to add an item to a List use the append
function.
 Code: listName.append(value)
 Note: Add element vs. update element

12. Other List Functions