Positional arguments in Python - Mini Project: Build & Apply

Using Positional Arguments in Python Functions

📖 Scenario: You are creating a simple calculator program that adds two numbers. You will use a function that takes two numbers as inputs and returns their sum.

🎯 Goal: Build a Python function that uses positional arguments to add two numbers and print the result.

📋 What You'll Learn

Create a function named add_numbers that takes exactly two positional arguments named num1 and num2.

Call the function add_numbers with two numbers as positional arguments.

Print the result returned by the function.

💡 Why This Matters

🌍 Real World

Functions with positional arguments are used everywhere in programming to perform tasks with inputs, like calculators, data processing, and more.

💼 Career

Understanding how to define and call functions with positional arguments is a fundamental skill for any programming job.

1

Create the function with two positional arguments

Write a function named add_numbers that takes two positional arguments called num1 and num2. Inside the function, return the sum of num1 and num2.

Python

# Your code here

Hint

Define the function with two names inside the parentheses. Use return to send back the sum.

2

Call the function with two numbers

Call the function add_numbers with the positional arguments 5 and 7, and store the result in a variable named result.

Python

def add_numbers(num1, num2):
    return num1 + num2

# Your code here

Hint

Use the function name followed by parentheses with two numbers inside, separated by a comma.

3

Print the result

Write a print statement to display the value stored in the variable result.

Python

def add_numbers(num1, num2):
    return num1 + num2

result = add_numbers(5, 7)

# Your code here

Hint

Use print(result) to show the sum on the screen.

4

Test with different numbers

Call the function add_numbers again with the positional arguments 10 and 20, store the result in result, and print it.

Python

def add_numbers(num1, num2):
    return num1 + num2

result = add_numbers(5, 7)
print(result)

# Your code here

Hint

Call the function with new numbers and print the result again to see the new sum.

Practice

1.

What are positional arguments in Python functions?

easy

A. Arguments passed in the exact order the function expects

B. Arguments passed with their names explicitly stated

C. Arguments that have default values

D. Arguments passed as a list or tuple

Solution

1. Step 1: Understand argument passing

   Positional arguments are passed to a function in the order the function defines its parameters.

2. Step 2: Differentiate from other argument types

   Unlike keyword arguments, positional arguments do not specify parameter names explicitly.

3. Final Answer:

   Arguments passed in the exact order the function expects -> Option A

4. Quick Check:

   Positional arguments = ordered values [OK]

Hint: Remember: order matters in positional arguments [OK]

Common Mistakes:

• Confusing positional with keyword arguments
• Thinking default values are positional arguments
• Assuming order doesn't matter

2.

Which of the following function calls uses positional arguments correctly?

def greet(name, age):
    return f"Hello {name}, you are {age} years old."

easy

A. greet(age=30, name='Alice')

B. greet(30, name='Alice')

C. greet('Alice', name=30)

D. greet('Alice', 30)

Solution

1. Step 1: Identify positional argument usage

   Positional arguments are passed without naming, in the order parameters are defined.

2. Step 2: Check each option

   greet('Alice', 30) passes 'Alice' then 30 matching (name, age) order correctly.

3. Final Answer:

   greet('Alice', 30) -> Option D

4. Quick Check:

   Positional call = values in order [OK]

Hint: Positional means no names, just order [OK]

Common Mistakes:

• Mixing keyword and positional arguments incorrectly
• Passing arguments in wrong order
• Using parameter names with positional arguments

3.

What is the output of this code?

def multiply(a, b):
    return a * b

result = multiply(3, 4)
print(result)

medium

A. 7

B. 34

C. 12

D. Error

Solution

1. Step 1: Understand function call with positional arguments

   Arguments 3 and 4 are passed as a and b respectively.

2. Step 2: Calculate the return value

   3 multiplied by 4 equals 12, so the function returns 12.

3. Final Answer:

   12 -> Option C

4. Quick Check:

   3 * 4 = 12 [OK]

Hint: Multiply arguments in order given [OK]

Common Mistakes:

• Adding instead of multiplying
• Concatenating numbers as strings
• Confusing argument order

4.

Find the error in this function call:

def divide(x, y):
    return x / y

print(divide(10))

medium

A. Missing one positional argument in the call

B. Division by zero error

C. Syntax error in function definition

D. No error, prints 10

Solution

1. Step 1: Check function parameters and call

   Function divide expects two positional arguments: x and y.

2. Step 2: Analyze the call with one argument

   Calling divide(10) provides only one argument, missing the second required positional argument y.

3. Final Answer:

   Missing one positional argument in the call -> Option A

4. Quick Check:

   Function needs 2 args, got 1 [OK]

Hint: Count arguments to match parameters [OK]

Common Mistakes:

• Assuming missing arguments default to zero
• Thinking one argument is enough
• Ignoring error messages

5.

Given this function:

def create_greeting(greeting, name, punctuation):
    return f"{greeting}, {name}{punctuation}"

Which call correctly uses positional arguments to produce Hello, Bob!?

hard

A. create_greeting('Bob', 'Hello', '!')

B. create_greeting('Hello', 'Bob', '!')

C. create_greeting(name='Hello', punctuation='!', 'Bob')

D. create_greeting(name='Bob', greeting='Hello', punctuation='!')

Solution

1. Step 1: Identify parameter order

   The function parameters are greeting, name, punctuation in that order.

2. Step 2: Match arguments to parameters positionally

   create_greeting('Hello', 'Bob', '!') passes 'Hello' to greeting, 'Bob' to name, and '!' to punctuation, producing the desired output.

3. Final Answer:

   create_greeting('Hello', 'Bob', '!') -> Option B

4. Quick Check:

   Order matches parameters for correct output [OK]

Hint: Match argument order to parameter order exactly [OK]

Common Mistakes:

• Swapping argument order
• Mixing positional and keyword incorrectly
• Assuming keyword arguments are positional