Jupyter Notebook best practices in Data Analysis Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of cell execution order in Jupyter Notebook

Consider this sequence of Jupyter Notebook cells executed in order. What is the output of the last cell?

Data Analysis Python

a = 5
b = 10

# Cell 1
c = a + b

# Cell 2
c = c * 2

# Cell 3
print(c)

A 20

B 15

C SyntaxError

D 30

💡 Hint

Remember that variables keep their values across cells unless redefined.

The first cell defines c as 5 + 10 = 15. The second cell doubles c to 30. The third cell prints 30.

🧠 Conceptual

intermediate

Best practice for notebook cell length

Which of the following is the best practice regarding the length of cells in a Jupyter Notebook?

A Keep cells short and focused on a single task or idea.

B Write very long cells to avoid too many cells in the notebook.

C Combine all code into one cell for faster execution.

D Use cells only for markdown and write all code in external scripts.

💡 Hint

Think about readability and debugging ease.

Short cells focused on one task improve readability and make debugging easier.

🔧 Debug

advanced

Identify the error in this notebook cell

What error will this Jupyter Notebook cell produce when run?

Data Analysis Python

import pandas as pd

df = pd.DataFrame({'A': [1, 2], 'B': [3, 4]})

print(df['C'])

A NameError

B TypeError

C KeyError

D No error, prints empty column

💡 Hint

Check if the column 'C' exists in the DataFrame.

Accessing a non-existent column 'C' in a DataFrame raises a KeyError.

🚀 Application

advanced

Improving notebook reproducibility

Which practice below best improves reproducibility of a Jupyter Notebook?

A Use random seeds only in some cells.

B Include all data loading and preprocessing steps in the notebook.

C Avoid comments to keep the notebook clean.

D Run cells in any order to save time.

💡 Hint

Think about what someone else needs to run your notebook and get the same results.

Including all data loading and preprocessing ensures the notebook can be run from start to finish with consistent results.

❓ visualization

expert

Effect of inline plotting in Jupyter Notebook

What is the effect of running `%matplotlib inline` in a Jupyter Notebook?

A Plots are displayed directly below the code cells as static images.

B Plots open in a new external window.

C Plots are saved automatically to disk.

D Plots are not displayed until the notebook is exported.

💡 Hint

Consider how plots appear inside the notebook interface.

The `%matplotlib inline` magic command makes plots appear inside the notebook below the code cells as static images.

Practice

1. Why is it important to use Markdown cells in a Jupyter Notebook?

easy

A. To add titles and explanations that make the notebook easier to understand

B. To run code faster

C. To store large datasets

D. To change the notebook's theme

Solution

1. Step 1: Understand the role of Markdown cells

   Markdown cells are used to write text, titles, and explanations, not code.

2. Step 2: Identify the benefit of explanations

   Adding explanations helps others and yourself understand the notebook's purpose and steps.

3. Final Answer:

   To add titles and explanations that make the notebook easier to understand -> Option A

4. Quick Check:

   Markdown cells = explanations [OK]

Hint: Markdown = text and titles, not code [OK]

Common Mistakes:

• Thinking Markdown runs code
• Using Markdown to store data
• Ignoring explanations

2. Which of the following is the correct way to add a comment in a Python code cell in Jupyter Notebook?

easy

A. // This is a comment

B. # This is a comment

C.

D. /* This is a comment */

Solution

1. Step 1: Recall Python comment syntax

   Python uses the hash symbol (#) to start a comment.

2. Step 2: Identify correct comment style

   Only # This is a comment uses the correct Python comment syntax.

3. Final Answer:

   # This is a comment -> Option B

4. Quick Check:

   Python comments start with # [OK]

Hint: Python comments start with # [OK]

Common Mistakes:

• Using // which is for other languages
• Using HTML comment syntax
• Using C-style comments

3. Consider this Jupyter Notebook code sequence:

1. x = 5
2. y = x + 2
3. print(y)

What will be the output after running all cells from top to bottom?

medium

A. 2

B. 5

C. Error

D. 7

Solution

1. Step 1: Trace variable assignments

   x is assigned 5, then y is assigned x + 2, which is 7.

2. Step 2: Understand print output

   Printing y will output 7.

3. Final Answer:

   7 -> Option D

4. Quick Check:

   5 + 2 = 7 [OK]

Hint: Follow variable values step-by-step [OK]

Common Mistakes:

• Assuming print shows x instead of y
• Forgetting to run cells in order
• Expecting error without reason

4. You have a notebook with cells:

1. a = 10
2. print(a)
3. a = 20

If you run cells in order 1, 3, 2, what will happen?

medium

A. Prints 20

B. Prints 10

C. Error: variable a not defined

D. Prints nothing

Solution

1. Step 1: Analyze cell execution order

   Cell 1 sets a=10, cell 3 sets a=20, then cell 2 prints a.

2. Step 2: Determine printed value

   Since a was last set to 20 before printing, print(a) outputs 20.

3. Final Answer:

   Prints 20 -> Option A

4. Quick Check:

   Last assignment before print = 20 [OK]

Hint: Run cells top to bottom to avoid confusion [OK]

Common Mistakes:

• Assuming print shows old value
• Thinking print runs before assignment
• Expecting error due to order

5. You want to share a Jupyter Notebook with a colleague. Which practice ensures they see your results correctly?

hard

A. Delete all Markdown cells to reduce size

B. Only run the last cell before sharing

C. Run all cells from top to bottom before sharing

D. Share only the .py script exported from notebook

Solution

1. Step 1: Understand notebook execution state

   Running all cells top to bottom ensures outputs match code and order.

2. Step 2: Identify sharing best practice

   Sharing a fully run notebook avoids confusion and missing outputs.

3. Final Answer:

   Run all cells from top to bottom before sharing -> Option C

4. Quick Check:

   Run all cells = consistent notebook [OK]

Hint: Always run all cells before sharing [OK]

Common Mistakes:

• Sharing without running cells
• Deleting Markdown removes explanations
• Sharing only scripts loses notebook features