Fall 2024 - P1
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3.5 Booleans 🔄
Student led teaching on Booleans. Learn how booleans are used in decision-making with logical operators (like less than or greater than).
Booleans 🔄
Basic Concept
Booleans either have a value of true or false
- true: Represents a logically true condition.
- false: Represents a logically false condition.
A Boolean Expression is an expression that produces a Boolean (Either true or false) when evaluated
- Common Boolean Expressions include equal to(=), greater than(>), less than(<), etc.
- These are called Relational Operators
Logical Operators allow you to combine multiple boolean expressions into one boolean output
Example 1
Create a program to check if a boolean is true. Create another to check if both are true or if either is true.
var variableA = true;
var variableB = false;
if (variableA == true) {
console.log("VariableA is true!");
} else if (variableA == false) {
console.log("VariableA is false!")
}
if (variableA == true && variableB == false) {
"variableA is true and variableB is false"
}
if (variableA == true || variableB == true) {
"Either variableA or variableB is true"
}
variableA = True
variableB = False
if variableA:
print("VariableA is true!")
else:
print("VariableA is false!")
if variableA and not variableB:
print("VariableA is true and Variable B is false")
if variableA or varaibleB:
print("Either variableA or variableB is true")
Relational Operators
- Equal to: a == b (True if a is equal to b)
- Not Equal to: a != b (True if a is not equal to b)
- Greater than: a > b (True if a is greater than b)
- Less than: a < b (True if a is less than b)
- Greater than or Equal to: a >= b (True if a is greater than or equal to b)
- Less than or Equal to: a <= b (True if a is less than or equal to b)
Example 2
Create a boolean expression to check if a number is greater than 10.
if (number > 10) {
console.log("number is greater than ten!");
} else {
console.log("number is not greater than ten!")
}
if number > 10:
print("number is greater than ten!")
else:
print("number is not greater than ten!")
Logical Operators
NOT
- NOT evaluates as true if the condition after not is false. If the condition is true, it evaluates as false.
AND
- AND evaluates as true if both conditions are true. If either or both conditions are false, it evaluates as false.
OR
- OR evaluates as true if either condition is true or if both conditions are true. If both are false, it evaluates as false.
Example 3
Create a boolean expression to check if a number is three digits.
if (number >= 100) and (number <= 999){
console.log("number is three digits!");
} else {
console.log("number is not three digits!")
}
if number >= 100 and number <= 999:
print("number is three digits!")
else:
print("number is not three digits!")