Python Expressions vs Statements: Practical Examples

This guide explains Expressions vs Statements: Practical Examples through a focused example and practical reasoning. No prior knowledge of this specific operation is required.

Understanding the Concept

An expression produces a value; a statement performs an action or controls execution. Assignments and if blocks are statements. A function call can be an expression used on its own as an expression statement.

When You Would Use This

Distinguish calculations from instructions that display their results.

Step-by-Step Example

unit_price = 6
unit_count = 5
order_total = unit_price * unit_count
print(order_total)
if order_total > 20:
    print("Large order")

How the Example Works

unit_price * unit_count evaluates to 30. Assignment binds the result to a name. The if statement chooses which following block to execute.

Example Output

30
Large order

Try It Yourself

Identify the expressions in total = (3 + 4) * 2 and name the statements in a short script.

Common Beginner Mistakes

• Treating = as an equality comparison operator.
• Expecting a statement such as if to be usable where a number is required.
• Confusing printing an expression with returning its value.

Key Takeaways

• An expression produces a value; a statement performs an action or controls execution.
• unit_price * unit_count evaluates to 30.
• Avoid this mistake: Treating = as an equality comparison operator.