Boolean
- A Boolean value is either true or false.
- A Boolean expression produces a Boolean value (true or false) when evaluated.
Conditional ("if") statements
- Affect the sequential flow of control by executing different statements based on the value of a Boolean expression.
IF (condition)
{
<block of statements>
}
The code in <block of statements> is executed if the Boolean expression condition evaluates to true; no action is taken if condition evaluates to false.
IF (condition)
{
<block of statements>
}
ELSE
{
<second block of statements>
}
The code in the first <block of statements> is executed if the Boolean expression condition evaluates to true; otherwise, the code in <second block of statements> is executed.
Example: Calculate the sum of 2 numbers. If the sum is greater than 10, display 10; otherwise, display the sum.
num1 = INPUT
num2 = INPUT
sum = num1 + num2
IF (sum > 10)
{
DISPLAY (10)
}
ELSE
{
DISPLAY (sum)
}
Hack 1
-
Add a variable that represents an age.
-
Add an ‘if’ and ‘print’ function that says “You are an adult” if your age is greater than or equal to 18.
-
Make a function that prints “You are a minor” with the else function.
## YOUR CODE HERE
age = int(input("Enter your age:"))
if age >= 18:
print("You are an adult.")
elif age > 0 and age < 18:
print("You are a minor.")
else:
print("Invalid age entered.")
Enter your age:15
You are a minor.
Relational operators:
- Used to test the relationship between 2 variables, expressions, or values. These relational operators are used for comparisons and they evaluate to a Boolean value (true or false).
Ex. a == b evaluates to true if a and b are equal, otherwise evaluates to false
- a == b (equals)
- a != b (not equal to)
- a > b (greater than)
- a < b (less than)
- a >= b (greater than or equal to)
- a <= b (less than or equal to)
Example: The legal age to work in California is 14 years old. How would we write a Boolean expression to check if someone is at least 14 years old?
age >= 14
Example: Write a Boolean expression to check if the average of height1, height2, and height3 is at least 65 inches.
(height1 + height2 + height3) / 3 >= 65
Hack 2
-
Make a variable called ‘is_raining’ and set it to ‘True”.
-
Make an if statement that prints “Bring an umbrella!” if it is true
-
Make an else statement that says “The weather is clear”.
## YOUR CODE HERE
is_raining = False
if is_raining:
print("Bring an unbrella!")
else:
print("The weather is clear.")
The weather is clear.
Logical operators:
Used to evaluate multiple conditions to produce a single Boolean value.
- NOT evaluates to true if condition is false, otherwise evaluates to false
- AND evaluates to true if both conditions are true, otherwise evaluates to false
- OR evaluates to true if either condition is true or if both conditions are true, otherwise evaluates to false
Example: You win the game if you score at least 10 points and have 5 lives left or if you score at least 50 points and have more than 0 lives left. Write the Boolean expression for this scenario.
(score >= 10 AND lives == 5) OR (score == 50 AND lives > 0)
Relational and logical operators:
Example: These expressions are all different but will produce the same result.
- age >= 16
- age > 16 OR age == 16
- NOT age < 16
Hack 3
-
Make a function to randomize numbers between 0 and 100 to be assigned to variables a and b using random.randint
-
Print the values of the variables
-
Print the relationship of the variables; a is more than, same as, or less than b
## YOUR CODE HERE
import random
a = random.randint(0,100)
b = random.randint(0,100)
print(f"The value of a is : {a}")
print(f"The value of b is : {b}")
if a > b:
print(f"{a} is greater than {b}.")
elif a < b:
print(f"{a} is less than {b}.")
else:
print(f"{a} is the same as {b}.")
The value of a is : 43
The value of b is : 88
43 is less than 88.
Homework
Criteria for above 90%:
- Add more questions relating to Boolean rather than only one per topic (ideas: expand on conditional statements, relational/logical operators)
- Add a way to organize the user scores (possibly some kind of leaderboard, keep track of high score vs. current score, etc. Get creative!)
- Remember to test your code to make sure it functions correctly.
#HOMEWORK
# The quiz contains questions related to Boolean values, Boolean expressions,
# conditional statements, relational operators, and logical operators.
# Import necessary modules
import getpass # Module to get the user's name
import sys # Module to access system-related information
# Function to ask a question and get a response
def question_with_response(prompt):
# Print the question
print("Question: " + prompt)
# Get user input as the response
msg = input()
return msg
# Define the number of questions and initialize the correct answers counter
questions = 5
correct = 0
# Personalized greeting message
# Collect the student's name
user_name = input("Enter your name: ")
print('Hello, ' + user_name + " running " + sys.executable)
print("You will be asked " + str(questions) + " questions.")
readyornot = input("Are you ready to take a test? ")
if readyornot == "Yes" or readyornot == "yes":
print("Alright, let's get started!")
# Question 1: Boolean Basics
# Ask a question about Boolean values and check the response
# Provide feedback based on the correctness of the response
answer1 = question_with_response("Question 1. Is 'True' a valid boolean value? ")
if answer1 == "Yes" or answer1 == "yes":
print(f"{answer1} is correct!")
correct += 1
else:
print(f"{answer1} is incorrect! The correct answer is 'yes'.")
# Question 2: Boolean Expressions
# Ask a question about Boolean expressions and their importance in programming
# Provide feedback based on the correctness of the response
answer2 = question_with_response("Question 2. Let word = 'monkey' and I want to check if the letter q exists. What will be the output? ")
if answer2 == "False" or answer2 == "false":
print(f"{answer2} is correct!")
correct += 1
else:
print(f"{answer2} is incorrect! The correct answer is 'False'.")
# Question 3: Conditional Statements
# Ask a question about the purpose of conditional (if-else) statements in programming
# Provide feedback based on the correctness of the response
answer3 = question_with_response("Question 3. Which statement is executed when a condition fails? ")
if answer3 == "else" or answer3 == "Else":
print(f"{answer3} is correct!")
correct += 1
else:
print(f"{answer3} is incorrect! The correct answer is 'else'.")
# Question 4: Relational Operators
# Ask a question about common relational operators in programming and provide examples
# Provide feedback based on the correctness of the response
answer4 = question_with_response("Question 4. What relational operator is used to check if a number is greater than or equal to another number?")
if answer4 == "<=":
print(f"{answer4} is correct!")
correct += 1
else:
print(f"{answer4} is incorrect! The correct answer is '<='.")
# Question 5: Logical Operators
# Ask a question about the use of logical operators in programming and provide examples
# Provide feedback based on the correctness of the response
answer5 = question_with_response("Question 5. What logical operator is used to check if either condition is true? ")
if answer5 == "Or" or answer5 == "or":
print(f"{answer5} is correct!")
correct += 1
else:
print(f"{answer5} is incorrect! The correct answer is 'or'.")
else:
print("Bye, see you another time!")
# Display the final score
# Calculate the percentage of correct answers and provide feedback
score = (correct/questions)*100
print(user_name + ", you scored " + str(correct) + "/" + str(questions) + " which is a " + "{:.2f}".format(score) + "%.")
Enter your name: aditya
Hello, aditya running /usr/bin/python3
You will be asked 5 questions.
Are you ready to take a test? yes
Alright, let's get started!
Question: Question 1. Is 'True' a valid boolean value?
yes
yes is correct!
Question: Question 2. Let word = 'monkey' and I want to check if the letter q exists. What will be the output?
false
false is correct!
Question: Question 3. Which statement is executed when a condition fails?
else
else is correct!
Question: Question 4. What relational operator is used to check if a number is greater than or equal to another number?
<=
<= is correct!
Question: Question 5. What logical operator is used to check if either condition is true?
or
or is correct!
aditya, you scored 5/5 which is a 100.00%.