 |
Fundamentals | .1 | .2 | .3 | .4 | .5 | .6 | .7 | .8 | .10 |
3.5 Booleans
Student led teaching on Booleans. Learn how booleans are used in decision-making with logical operators.
Boolean
- A Boolean value is either true or false.
- A Boolean expression produces a Boolean value (true or false) when evaluated.
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
- In most states, the minimum age to drive is 16. How would we write a boolean expression to check if someone is at least 16 years old?
age >= 16 - Write a boolean expression to check if the average of grade1, grade2, and grade3 is at least 70.
(grade1 + grade2 + grade3)/3 >= 70 - Write a code to check if the temperature is less than 90 degrees
temp < 90
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)
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
Hacks
Review each of the sections above and produce …
- Look up De Morgan’s Law. What is it, and how can it apply to your code? Make a blog post about it.
- Create a truth table using Python (hint: These tables come up during the AP Exam). You will need to use libraries such as itertools. Here is an image of how the truth table should look:
