Udayan Das; Aubrey Lawson; Chris Mayfield; Narges Norouzi

Highlights from this chapter include:

Booleans represent a value of True or False.
Comparison operators compare values and produce True or False.
Logical operators take condition operand(s) and produce True or False.
Operators are evaluated in order according to precedence and associativity.
Conditions are expressions that evaluate to True or False.
Decision statements allow different paths of execution (branches) through code based on conditions.
Decision statements can be nested inside other decision statements.
Conditional expressions are single-line versions of if-else statements.

At this point, you should be able to write programs that evaluate conditions and execute code statements accordingly with the correct order of operations. The programming practice below ties together most topics presented in the chapter.

Function	Description
bool(x)	Converts `x` to a Boolean value, either `True` or `False`.
Operator	Description
`x == y` (Equality)	Compares the values of `x` and `y` and returns `True` if the values are equal and `False` otherwise. Ex: `10 == 10` is `True`.
`x != y` (Inequality)	Compares the values of `x` and `y` and returns `True` if the values are inequal and `False` otherwise. Ex: `7 != 4` is `True`.
`x > y` (Greater than)	Compares the values of `x` and `y` and returns `True` if the `x` is greater than `y` and `False` otherwise. Ex: `9 > 3` is `True`.
`x < y` (Less than)	Compares the values of `x` and `y` and returns `True` if the `x` is less than `y` and `False` otherwise. Ex: `9 < 8` is `False`.
`x >= y` (Greater than or equal)	Compares the values of `x` and `y` and returns `True` if the `x` is greater than or equal to `y` and `False` otherwise. Ex: `2 >= 2` is `True`.
`x <= y` (Less than or equal)	Compares the values of `x` and `y` and returns `True` if the `x` is less than or equal to `y` and `False` otherwise. Ex: `8 <= 7` is `False`.
`x and y` (Logical)	Evaluates the Boolean values of `x` and `y` and returns `True` if both are true. Ex: `True and False` is `False`.
`x or y` (Logical)	Evaluates the Boolean values of `x` and `y` and returns `True` if either is true. Ex: `True or False` is `True`.
`not x` (Logical)	Evaluates the Boolean value of `x` and returns `True` if the value is false and `False` if the value is true. Ex: `not True` is `False`.
Decision statement	Description
`if` statement	# Statements before if condition: # Body # Statements after
`else` statement	# Statements before if condition: # Body else: # Body # Statements after
`elif` statement	# Statements before if condition: # Body elif condition: # Body else: # Body # Statements after
Nested `if` statement	# Statements before if condition: if condition: # Body else: # Body else: if condition: # Body else: # Body # Statements after
Conditional expression	`expression_if_true if condition else expression_if_false`

Table 4.5 Chapter 4 reference.

4.8 Chapter summary