Package structure and usage in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the module mymodule from the package mypackage.

Python

from mypackage import [1]

Drag options to blanks, or click blank then click option'

Amypackage

Bpackage

Cmodule

Dmymodule

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to import the package name instead of the module.

Using generic words like 'module' or 'package' instead of the actual module name.

You import the module by its name inside the package, so mymodule is correct.

2fill in blank

medium

Complete the code to import the function greet from the module mymodule inside the package mypackage.

Python

from mypackage.mymodule import [1]

Drag options to blanks, or click blank then click option'

Agreet

Bmypackage

Cmymodule

Dfunction

Attempts:

3 left

💡 Hint

Common Mistakes

Importing the module name instead of the function.

Using generic words like 'function' instead of the actual function name.

You import the function by its name, so greet is correct.

3fill in blank

hard

Fix the error in the import statement to correctly import the greet function from mypackage.mymodule.

Python

import mypackage.[1].greet

Drag options to blanks, or click blank then click option'

Amymodule

Bmypackage

Cgreet

Dfunction

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to import a function directly using dot notation.

Using the package name twice.

You cannot import a function directly using dot notation in an import statement like this. You must import the module first. So the correct fix is to import the module mymodule.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each module name in modules to its length, but only if the length is greater than 5.

Python

{module: len(module) for module in [1] if len(module) [2] 5}

Drag options to blanks, or click blank then click option'

Amodules

B>

C<

Dmodule_list

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable name for the list.

Using the wrong comparison operator.

We iterate over the list named modules and check if the length of each module name is greater than 5.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps each module name in modules to its uppercase version, but only if the module name starts with the letter 'a'.

Python

{ [1]: [2] for [3] in modules if [3].startswith('a') }

Drag options to blanks, or click blank then click option'

Amodule

Bmodule.upper()

Dmod

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in the comprehension.

Not calling upper() on the module name.

Using the wrong variable as key or value.

We use module as the key and its uppercase version as the value, iterating over module in modules.

Practice

1. What is the main purpose of the __init__.py file in a Python package?

easy

A. To mark a directory as a Python package

B. To execute the main program

C. To store global variables

D. To compile Python files

Solution

1. Step 1: Understand the role of __init__.py

   The __init__.py file tells Python that the directory should be treated as a package.

2. Step 2: Differentiate from other options

   It does not execute the main program, store global variables, or compile files; its main role is package identification.

3. Final Answer:

   To mark a directory as a Python package -> Option A

4. Quick Check:

   __init__.py marks packages [OK]

Hint: Remember: __init__.py makes folder a package [OK]

Common Mistakes:

• Thinking __init__.py runs main code automatically
• Confusing it with a script file
• Assuming it compiles Python files

2. Which of the following is the correct way to import the module utils from a package named mypackage?

easy

A. import mypackage.utils

B. from utils import mypackage

C. import utils.mypackage

D. from mypackage import utils

Solution

1. Step 1: Recall Python import syntax for packages

   To import a module from a package, use from package_name import module.

2. Step 2: Match syntax to options

   from mypackage import utils matches this syntax: from mypackage import utils.

3. Final Answer:

   from mypackage import utils -> Option D

4. Quick Check:

   Import module with 'from package import module' [OK]

Hint: Use 'from package import module' to import modules [OK]

Common Mistakes:

• Reversing package and module names
• Using incorrect import order
• Trying to import module as package

3. Given this package structure:

mypackage/
  __init__.py
  math_ops.py
  string_ops.py

And this code:

from mypackage import math_ops
print(math_ops.add(2, 3))

If math_ops.py contains a function def add(a, b): return a + b, what is the output?

medium

A. None

B. TypeError

C. 5

D. NameError

Solution

1. Step 1: Understand the import and function call

   The code imports math_ops from mypackage and calls math_ops.add(2, 3).

2. Step 2: Evaluate the function output

   The function add returns the sum of 2 and 3, which is 5.

3. Final Answer:

   5 -> Option C

4. Quick Check:

   2 + 3 = 5 [OK]

Hint: Trace function call and return value carefully [OK]

Common Mistakes:

• Forgetting to call the function with parentheses
• Confusing module and function names
• Assuming import fails without __init__.py content

4. You have a package folder named tools with modules calc.py and format.py. You try to run:

from tools import calc
print(calc.multiply(4, 5))

But get ModuleNotFoundError. What is the most likely cause?

medium

A. Function multiply does not exist in calc.py

B. Missing __init__.py file in the tools folder

C. Syntax error in import statement

D. Python version is too old

Solution

1. Step 1: Understand ModuleNotFoundError cause

   This error often means Python does not recognize the folder as a package.

2. Step 2: Check package structure requirements

   Without __init__.py, Python won't treat 'tools' as a package, causing import failure.

3. Final Answer:

   Missing __init__.py file in the tools folder -> Option B

4. Quick Check:

   __init__.py missing causes ModuleNotFoundError [OK]

Hint: Always add __init__.py to package folders [OK]

Common Mistakes:

• Assuming function absence causes ModuleNotFoundError
• Ignoring package folder structure
• Blaming Python version without checking files

5. You want to create a package datautils with submodules clean.py and transform.py. You want users to import clean_data function directly from datautils like this:

from datautils import clean_data

Which code should you add to datautils/__init__.py to enable this?

hard

A. from .clean import clean_data

B. import clean_data from clean

C. from clean import clean_data

D. import clean.clean_data

Solution

1. Step 1: Understand relative imports in packages

   Inside __init__.py, use relative import with dot: from .clean import clean_data.

2. Step 2: Confirm correct syntax for exposing functions

   This syntax makes clean_data available directly from datautils.

3. Final Answer:

   from .clean import clean_data -> Option A

4. Quick Check:

   Use 'from .module import func' in __init__.py [OK]

Hint: Use relative import with dot in __init__.py [OK]

Common Mistakes:

• Using absolute import without dot inside __init__.py
• Wrong import syntax like 'import clean_data from clean'
• Trying to import without __init__.py setup