Unit Notes and Homework (Day 1)
3.1 & 3.2
Lesson
Variables
A variable is an abstraction inside a program that can hold a value.
It organizes data by labeling it with a descriptive name.
It consists of three parts: name, value, and type.
Using meaningful variables names helps with readability of program code and understanding of what values are represented by the variables.
Variables should not be specific.
Not too vague either.
Use 1-2 capitalized letters
No spaces
Types of data:
- Integer: A number
- Text/string: A word
- Boolean: Data that determines if something is true or false
A list of data can also be stored in variables. Why is that useful?
- print/retrieve specific values in the list without creating a lot of variables
- easily remove/add/change items into the list
num1 = 5
num2 = 9
num1 = num2
print(num1)
print(num2)
num1 = 15
num2 = 25
num3 = 42
num2 = num3
num3 = num1
num1 = num2
print(num1)
print(num2)
print(num3)
num2 += num1
print(num1)
print(num2)
print(str(num1)+ str(num2))
print(num1 + num2)
Data Abstraction
Method used in coding to represent data in a useful form, by taking away aspects of data that aren't being used in the situation
Variables and lists are primary tools in data abstraction
Provides a separation between the abstract properties of a data type and the concrete details of its representation
Lists & Strings
List = ordered sequence of elements
Element = individual value in a list that is assigned to a unique index
Index = a way to reference the elements in a list or string using natural numbers; each element of a string is referenced by an index
String = ordered sequence of characters (Letters, numbers, special characters)
Managing the Complexity of a Program through Data Abstraction
Data abstractions help manage complexity in programs by giving a collection of data a name without referencing the specific details of the representation
Developing a data abstraction to use in a program can result in a program that is easier to develop and maintain
Using Lists as Data Abstractions
What are Lists?
Allow for data abstraction
Bundle variables together
Store multiple elements
Allows multiple related items to be treated as a single value
Give one name to a set of memory cells
Can keep adding elements to it as needed
Can store elements as a single variable by using a list
3 Types of List Operations
Assigning values to a list at certain indices
Creating an empty list and assigning it to a variable
Assigning a copy of one list to another list (setting one list equal to another list)
colorsList=["pink", "yellow", "green", "blue", "orange"]
print(colorsList)
colorsList=[] # can be used if you want to create a list that can be filled with values later
# copy of the list is made; the list isn't sorted in place
def Reverse(lst): # defining variable: lst
new_lst = lst[::-1]
return new_lst
lst = ["pink", "green", "purple", "yellow", "orange", "blue", "black"]
print(Reverse(lst)) # reverse 1st
color1="green"
color2="red"
color3="pink"
color4="purple"
color5="blue"
color6="brown"
print(color1)
print(color2)
print(color3)
print(color4)
print(color5)
print(color6)
# OR
colorList=["green", "red", "pink", "purple", "blue", "brown"]
for i in colorList:
print(i)
questions = 3
correct = 0
# Use a dictionary for the questions
quesList = ["To be or not to be?", "What's your name?", "How was break?", "Is this homework?"]
# Use a dictionary for the correct solutions
soluList = ["idk", "mani", "fine", "yea"]
for i in quesList:
print(i)
value1 = input ("Q1")
value2 = input ("Q2")
value3 = input ("Q3")
value4 = input ("Q4")
for n in soluList:
if value1 == n:
correct += 1
for x in soluList:
if value2 == x:
correct += 1
for z in soluList:
if value3 == z:
correct += 1
for y in soluList:
if value4 == y:
correct += 1
print("Final score: " + str(correct))