Decision Structures

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The if Statement

• Control structure → directs the order of statement execution
  • Sequence structure → statements executed in the order they appear
  • Decision/Selection structure → executes actions based on a condition

Flowchart Representation

flowchart TD
    A[Start] --> B{Condition}
    B -- True --> C[...]
    B -- False --> D[...]

Python Syntax

if condition:
    # statement(s)

Boolean Variables

• References one of two values: True or False
• Represented by the bool type in Python
• Commonly used for flags, a variable to determine if a condition exists

Boolean Expressions

• Tested by the if statement to determine truthiness
  • IE: a > b → True if a is greater than b, False otherwise

Relational Operators

• > → greater than
• < → less than
• >= → greater than or equal to
• <= → less than or equal to
• == → equal to
• != → not equal to

The not Operator

• Reverses the logical value of a boolean expression
  • IE: not False → True (and vise-versa)

Checking Numeric Ranges

• To check within a range, use and
  • IE: x >= 18 and x <= 21
• To check outside a range, use or
  • IE: x < 10 or x > 20

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