Positional arguments in Python

Introduction

Positional arguments let you send information to a function in order. The function uses these values to work.

When you want to give a function specific values to use in order.

When the order of information matters, like giving a name then an age.

When calling simple functions that expect a fixed number of inputs.

When you want to keep your code easy to read by following the function's expected order.

Syntax

Python

def function_name(arg1, arg2, arg3):
    # use arg1, arg2, arg3 inside

function_name(value1, value2, value3)

Arguments are matched to parameters by their position, first to first, second to second, and so on.

If you change the order of values when calling, the function will get different data.

Examples

This sends "Alice" as the first argument and 30 as the second. The function prints a greeting.

Python

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

greet("Alice", 30)

The function adds two numbers given in order and returns the sum.

Python

def add(x, y):
    return x + y

result = add(5, 3)
print(result)

Here, "dog" is the first argument and "Buddy" is the second, matching the parameters.

Python

def describe_pet(animal, name):
    print(f"I have a {animal} named {name}.")

describe_pet("dog", "Buddy")

Sample Program

This program defines a function that takes three positional arguments and prints a sentence using them.

Python

def introduce(first_name, last_name, age):
    print(f"My name is {first_name} {last_name} and I am {age} years old.")

introduce("John", "Doe", 25)

Important Notes

Make sure to give the arguments in the exact order the function expects.

If you give fewer or more arguments than the function needs, Python will show an error.

You can mix positional arguments with keyword arguments, but positional ones must come first.

Summary

Positional arguments send values to a function in the order the function expects.

The order of arguments is important and changes how the function works.

They are simple and common for passing data to functions.

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