Python 3.1.1.11 LAB: Essentials of the if-else statement

 PCAP 3.1.1.11 LAB: Essentials of the if-else statement

if-else

If you're taking PCAP - Programming Essentials In Python , you may have encountered this question in 3.1.1.11 LAB: Essentials of the if-else statement.

Scenario

Once upon a time there was a land - a land of milk and honey, inhabited by happy and prosperous people. The people paid taxes, of course - their happiness had limits. The most important tax, called the Personal Income Tax (PIT for short) had to be paid once a year, and was evaluated using the following rule:

if the citizen's income was not higher than 85,528 thalers, the tax was equal to 18% of the income minus 556 thalers and 2 cents (this was the so-called tax relief)

if the income was higher than this amount, the tax was equal to 14,839 thalers and 2 cents, plus 32% of the surplus over 85,528 thalers.

Your task is to write a tax calculator.

It should accept one floating-point value: the income.

Next, it should print the calculated tax, rounded to full thalers. There's a function named round() which will do the rounding for you - you'll find it in the skeleton code in the editor.

Note: this happy country never returns money to its citizens. If the calculated tax is less than zero, it only means no tax at all (the tax is equal to zero). Take this into consideration during your calculations.

Look at the code in the editor - it only reads one input value and outputs a result, so you need to complete it with some smart calculations.

Test your code using the data we've provided.

Test Data

Sample input: 10000

Expected output: The tax is: 1244.0 thalers

Sample input: 100000

Expected output: The tax is: 19470.0 thalers

Sample input: 1000

Expected output: The tax is: 0.0 thalers

Sample input: -100

Expected output: The tax is: 0.0 thalers 

The Code:

income = float(input("Enter the annual income: "))

max_income = 85528 #You can use a varibale or just subsutitute max_income with 85528

if income <= max_income:

    tax = income * .18  - 556.2 # 18% of the income minus 556.2

elif income > max_income:

    tax = 14839.2 + .32 * ( income - max_income)

# 14839 thalers and 2 cents, plus 32% of the surplus over 85,528 thalers.

if tax <0:

    tax = 0.0

tax = round(tax, 0)

print("The tax is:", tax, "thalers")

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The Role of the if-else Statement

The if-else statement is the backbone of decision-making in Python. It lets a program execute different blocks of code depending on whether a condition is true or false, which is how a script reacts to changing input rather than running the same steps every time.

In the essentials of this Lab, the key is to reason carefully about which branch runs for each input. Python evaluates the condition after if; if it is truthy the indented block beneath it executes, and otherwise the block beneath else runs. Getting the ordering right matters because only the first matching branch is taken when elif is used, so conditions that overlap should be arranged from most to least specific.

Common Mistakes to Avoid

• Forgetting the colon at the end of the if or else line causes a syntax error.
• Using inconsistent indentation makes Python raise a block-related error or run the wrong code.
• Testing a value after it has already been changed, which can produce results different from what the scenario expects.
• Overlapping elif conditions that are not ordered from most to least specific, so an earlier branch catches cases meant for a later one.

Key Takeaways

• if and else choose between two blocks based on a condition.
• Conditions are evaluated in order and only the first matching branch executes.
• Colons and consistent indentation are essential to valid syntax.
• Think through the test data by hand to verify which branch each input reaches.

Frequently Asked Questions

What is the difference between if-else and if-elif-else?

if-else handles two cases, while if-elif-else handles several. The elif keyword lets you chain additional conditions; the first true one runs.

Can an if-else statement exist without an else?

Yes. The else is optional, and an if on its own simply runs its block when the condition is true and does nothing otherwise.

Why does Python use indentation instead of braces?

Python uses indentation to define blocks as part of its design philosophy of readable code. Consistent indentation is therefore required syntax rather than only a style preference.