Student Teaching Lesson 3.1 & 3.2
Student Teaching Notes and Homework (3.1 & 3.2)
3.1 & 3.2
Variables
- Variables organize data by labeling it with a descriptive name
- contains a name, value, and type
- NAMING:
- use general terms
- keep it concise
- use consistent notation (caps, etc...)
- don't make it too vague
- DON'T USE SPACES
- TYPES:
- Integer - a number
- Text/string - a word or string of characters
- Boolean - data that determines if something is true or false
- A list of data can be stored as a variable
- more organized
- can be indexed
- NAMING:
- contains a name, value, and type
Assignments
- Operators that allows a program to change the value represented by a variable
- Used to assign values to variables
- =
- Assigns value of the right side to the left side
- a=b
- Outcome: b
- +=
- Add right side operand with left side operand and then assign to left operand
- a+=b
- Outcome: a+b
- -=
- Subtract right operand from left operand and then assign to left operand: True if both operands are equal
- a-=b
- Outcome: a-b
- same thing for *= and /=
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 and 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
- Example of a list with colors
| Index | Element |
|---|---|
| 1 | Green |
| 2 | Blue |
| 3 | Purple |
| 4 | Pink |
- At index 1, the element is green, at index 2, the element is blue, etc...
Managing Lists
-
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)
-
Managing complexity
- Helps improve readability
- Reduces the need for new variables as more data is collected
- Can easily update data
- Can easily convert data to different forms
Practice
colorList=["green", "red", "pink", "purple", "blue", "brown"]
for i in colorList:
print(i)
Homework
You will turn in a program that utilizes lists and variables as it's primary function, options could be a quiz, a sorter, database, or wherever your imagination brings you. You will be graded on how well you understood the concepts and if you used anything other than just the simplest parts.
QandA = {
"#1) What is the study of the human body called?": "anatomy",
"#2) What is the main focus of Unit 3 in Comp Sci": "algorithms",
"#3) What is the most popular programming language": "javascript",
"#4) A microphone, keyboard, and mouse are all different types of what?": "input devices",
"#5) What is the HyperText Markup Language commonly referred to as?": "html",
}
def qandresp(question): # display question, return inputted response
print(question)
resp = input()
return resp
correct = 0
# Setup
print("Current number of questions: " + str(len(QandA)))
# iterate over each key
for key in QandA:
rsp = qandresp(key) # save user's response to a variable rsp
rsp = rsp.lower() # answer is case sensitive, so match response to lowercase for answer key to work
if rsp == QandA[key]: # check if the response is equal to the answer in the dictionary
print(f"Correct! Your answer was {rsp}")
correct += 1
else:
print(f"{rsp} is incorrect")
percent = str(round(correct/len(QandA), 2)*100) # calculate percentage
print("You scored " + str(correct) +"/" + str(len(QandA)))
print(f"This is {percent}%") # print score and percentage