1. Intro to CS Sept 22/23, 2015

2. Today
Review Project 1
Unit 2 Introduction
Lists
Project 2

3. Review Project 1 (Mario)
Mario/Hero moves left, right, up (Motion Category)
Villian continuously slides back and forth (Motion Category)
Scenary Sprites move if Mario/Hero moves (broadcasting & receiving; sense of dependency) (Control Category
Scenary: When Hero and Villian are touching, game over, and all scripts stop.

4. Shopping List

5. List Examples PB & J ingredients A set of numbers Letters in words
Things to buy at the grocery store

6. What is a list?
A finite , ordered, collection of  items, where the same value may occur more than once

7. Lists Finite – having a limit or bounds
Ordered – the sequence of items matters
Collection – a bundle of items

8. List is a Data Type
A regular variable stores a single item
a = 1
A list can store multiple items of data
nums = [15, 3, 15, 18]
The data is stored sequentially in list
items, aka, list values

9. The items are indexed starting at 1
List index and length
The items are indexed starting at 1
[Python index starts from 0]
The list has a finite length of 4
Index 1 2 3 4
Value 15 7 18

10. groceryList = [vegetables, fruit, milk]
List of String Values
groceryList = [vegetables, fruit, milk]
This list has a finite length of 3
List can have different item types
Index 1 2 3
Value
vegetables
fruit
milk

11. List Operations
Initialization
Indexing
Length
Add
Insert

12. Making Lists in SNAP! Creating a List is like creating a Variable …kind of.
Step 1.
Step 2.

13. Initialization
Python: groceryList = [vegetables, fruit, milk]

14. Item, Index and Length
Items are numbered with an index (starting at 1)
A list has a notion of length
1 min
EXAMPLE: “vegetables” is an item Its index is “1”
The list “groceryList” has a length =3

15. Indexing an Item in List
Returns the item in the list with index 1: “vegetables”
Can be used in other blocks such as Boolean or Say
The Python way, groceryList[0]
30 secs

16. Length Returns the length of the list
Can be used in other blocks such as Boolean or Say
The Python way, len(groceryList)
30 secs

17. Add The add operation put the values at the end
Assigns the “groceryList” variable to an empty list
Adds “vegetables” to the end of the list
Adds “fruit” to the end of the list
Adds “milk” to the end of the list
The add operation put the values at the end
In Python, it’s called “append”

18. Insert create empty list add “fruit” to end add “milk” to end
add “vegetables” to end
add “fruit” to end
add “milk” to end
30 secs
insert “eggs” at position 1

19. Compare Add and Insert “Add” places “thing1” at the end of the list
“Insert” places “thing2” at the designated spot, 1
30 secs

20. Exercise 1: Making a Shopping List
Make a list with the same order as this one.
Use at least one “insert” block.
Save your work in SNAP! as “Shopping List”

21. What worked? What was difficult?
Exercise 1 Recap:
What worked?
What was difficult?

22. Review: List
A finite, ordered, collection of  items, where the same value may occur more than once
In computer science, List is a Data Type that can store multiple items of data
Items in a list can be indexed
List has a length

23. The items are indexed starting at 1
List index and length
The items are indexed starting at 1
[Python index starts from 0]
The list has a finite length of 4
Index 1 2 3 4
Value 15 7 18

24. Initialization
Python: groceryList = [vegetables, fruit, milk]

25. Indexing an Item in List
Returns the item in the list with index 1: “vegetables”
Can be used in other blocks such as Boolean or Say
The Python way, groceryList[0]
30 secs

26. Length Returns the length of the list
Can be used in other blocks such as Boolean or Say
The Python way, len(groceryList)
30 secs

27. Compare Add and Insert “Add” places “thing1” at the end of the list
“Insert” places “thing2” at the designated spot, 1
30 secs

28. List Operations Initialization Iterate Indexing Delete Length
Add
Insert
Iterate
Delete
Clear – delete all
Replace

29. Iteration – For each For each – iterate over items directly
30 secs
For each – iterate over items directly
Python: for item in groceryList:

30. Iteration – For loop
For Loop – iterate over items using index
30 secs

31. Iteration - Repeat
“Repeat”
30 secs

32. Exercise iteration: Make a global groceryList
Make an iterateForEach block that takes inputList as argument and iterate over inputList to say the items
Make a showGroceryList that invokes iterateForEach

33. Iterate: For Each

34. Duplicate Items
30 secs

35. Delete “Delete all” deletes all items in the list
30 secs
“Delete all” deletes all items in the list
Python del groceryList[:]

36. Replace
30 secs

37. Project #2: Mario with Lists

38. Mario List
1.  Learn how to access already existing lists - xList & yList - in order to make Mario jump
2. Create an empty list - performanceList.
3. Append values into the performanceList -  which will record the speeds at which Mario successfully jumps over the gremlin.

39. List Operations
Initialization
Indexing
Length
Add
Insert

40. SNAP! User’s Manual http://snap.berkeley.edu/SnapManual.pdf
Ch 1. Blocks, Scripts, Sprites
Ch 2. Saving and Loading projects
Ch 3. Building a Block
Ch 4. First Class Lists
Ch 5. Typed Inputs
Ch 6. Procedures as Data
Ch 7. Object Oriented Programming
Ch 8. The Outside World
Ch 9. Continuations
Ch 10. User Interface Elements
Index

41. Project 2 (Mario with Lists)

42. Reminders Read Chapter 2 before the start of class on Wednesday
Test on Friday next week
on SNAP!

43. Unit 2: Looking ahead Monday Wednesday Friday 14 Unit 2 start - Lists16
Quiz on BtB Chapter 2 18 21 23 25
Test
Project #2 due 6pm
SCHOOL BREAK 5
Start Unit 3 - Python 7
Quiz on BtB Chap 3 9