Lecture 4: Boolean Expressions and Conditionals

Flashcards testing core vocabulary and concepts related to procedural knowledge, Boolean logic, relational and logical operators, order of operations, and conditional statements in Python.

Procedural Knowledge

Knowledge of how to do things through described processes, instructions, recipes, or computer algorithms.

Boolean Expression

An expression that evaluates to a Boolean value, which can only be either True or False.

Relational Operators

Operators used to compare two values, such as equality ($==$), inequality ($!=$), less than ($<$), greater than ($>$), less than or equal to ($<=$), and greater than or equal to ($>=$).

Equality Operator ($==$)

A relational operator that tests whether two values are equal, written with two equal signs to distinguish it from the single-equal variable assignment operator.

Boolean Operators

Logical operators including $\text{and}$, $\text{or}$, and $\text{not}$ that operate on Boolean values to form complex logical decisions.

Logical operator: $\text{and}$

A Boolean operator that evaluates to True if and only if both input conditions are True; otherwise, it evaluates to False.

Logical operator: $\text{or}$

A Boolean operator that evaluates to True if at least one input condition is True; it evaluates to False only if both conditions are False.

Logical operator: $\text{not}$

A unary Boolean operator that reverses a Boolean value, turning True to False and False to True.

Conditional Evaluation Order

The order of precedence across expression types: Mathematical operators are evaluated first, followed by Relational operators, followed by Boolean operators (with $\text{not}$ evaluated before $\text{and}$, and $\text{and}$ evaluated before $\text{or}$).

if Statement

A conditional control statement that executes a designated block of code if and only if its associated Boolean condition evaluates to True.

Indentation (Python)

A required syntactic structure in Python (typically 4 spaces or 1 tab) used to group statements inside a conditional or control block.

if-else Statement

A conditional structure with two execution paths: one executed when the Boolean condition is True, and another executed when it is False.

if-elif-else Statement

A multi-branch conditional structure that sequentially checks multiple Boolean expressions and executes ONLY the code block associated with the FIRST condition that evaluates to True.

Nested Branches

The technique of placing a conditional statement (if, if-else, or if-elif-else) inside another conditional block to structure complex or ordered decision logic.

in Operator

A Boolean operator that tests whether an exact value or sub-sequence exists within a given sequence, such as a string.