Structured Types

Question 1

Tubles

Answer 1

• an ordered sequence of elements
• immutable
• represented with parentheses

Question 2

Tubles - more

Answer 2

• Swap variables (x, y) = (y, x)

- Return more than one value from a function

Question 3

Lists

Answer 3

• Ordered sequence of information
• Denoted by square brackets
• Contains a list of elements
• Is mutable

Question 4

Functions as Objects

Answer 4

first class objects:

• have types
• can be elements of data structures like lists
• can appear in expressions
  
  • as part of an assignment statement
• as an argument to a function!
• useful to use functions as arguments when coupled with lists -> higher order programming (hop)

Question 5

Generalization of HOPs

Answer 5

• Python provides a general purpose HOP -> map
• simple form is a unary
• general from is an n-ary

Question 6

Dictionary

Answer 6

Store pairs of data:

• key
• value

Question 7

Dictionary lookup

Answer 7

• similar to indexing into a list
• looks up the key
• returns the value associated with the key
• if key not found -> error

Question 8

Dictionary - values

Answer 8

• immutable and mutable
• can be duplicates
• can be lists, tuples, dictionaries

Question 9

Dictionary - keys

Answer 9

• Unique
• immutable
• careful with using floats!
• no order to keys or values!

Question 10

list
vs
dictionary

Answer 10

lists:
- ordered, look-up by int. index, indices have an order, index is an integer
dict:
- matches 'keys' to 'values'
- look-up one item by another item
- no order is guaranteed
- key can be any immutable type

Question 11

global variables

Answer 11

can be dangerous
- breaks the scope
- allows for side effects
BUT can be convenient when want to keep track of information inside a function