PCDE Course: Module 9 Content

Associated Notes

Codio Coding Activity 9.1: Debugging Your Code

1. Debugging Your Code

Debugging the Function score()

The code on the left defines a function score() that takes no arguments, but defines the global variable score throughout the program. Modify the code on the left so that the output of your program is 0. In fact, if you try to run the following command python Q1.py in the Terminal window, you see that the output produced is not the one that you would expect.

Below, you have been provided with a simple debugging tool: Code Visualizer. Click on the button Code Visualizer to launch it and debug your code. Feel free to resize the windows to see the complete output.

HINT: You must indent the blocks below. You can do so by dragging them.

Solution

def score():
    global score
    score = 0
    print(score)
score()

2. Debugging Your Code II

Debugging the Function add_underscores()

The code on the left defines a function add_underscores() that takes a single string object word as an argument and returns a new string containing a copy of the word with each character surrounded by underscores. For example, add_underscores("python") should return _p_y_t_h_o_n_.

However, if you try to run the following command python Q2.py in the Terminal window, you see that the output produced is not the one that you would expect.

Below, you have been provided with a simple debugging tool: Code Visualizer. Click on the button Code Visualizer to launch it and debug your code. Feel free to resize the windows to see the complete output.

Solution

def add_underscores(word):
    new_word = "_"
    for i in range(len(word)):
        new_word =new_word+ word[i] + "_"
    return new_word

word = "python"
print(add_underscores(word)

3. Debugging Your Code III

Debugging the Function average()

The code on the left contains the function average that takes two numbers as input and returns their average.

However, if you try to run the following command python Q3.py in the Terminal window, you will see that the code has bugs and the output produced is not the one that you would expect.

Below, you have been provided with a simple debugging Tool: Code Visualizer. Click on the button Code Visualizer to launch it and debug your code. Feel free to resize the windows to see the complete output.

Problem

def average(x, y):
    result = x+y/2
    return result

print(average(4.0, 9.0)) # should print 6.5

Solution

def average(x, y):
    result = 0
    result += x
    result += y
    result /= 2
    return result

print(average(4.0, 9.0)) # should print 6.5

4. Debugging Your Code IV

Debugging the Function buggy_function()

The function buggy_function() on the left has exactly one bug. The function should return True if the input x is either an even integer less than or equal to 10, or an odd integer greater than 10. Otherwise, the function should return False. However, when you run the function in the Terminal window via python Q4.py with the argument 14, you see an unexpected result.

Below, you have been provided with a simple debugging Tool: Code Visualizer. Click on the button Code Visualizer to launch it and debug your code. Feel free to resize the windows to see the complete output.

Problem

def buggy_function(x):
    is_even = (x % 2 == 0)

    if type(x) != int:
        return False

    if x <= 10:
        if is_even:
            return True
    if x > 10:
        if not is_even:
            return True
    else:
        return False

      
test = buggy_function(14)
print(test)

Solution

def buggy_function(x):
    if type(x) != int:
        return False
    if x > 10 and x % 2:
        return True
    if x <= 10 and not x % 2:
        return True
    return False

      
print(f'Test x = 14: {buggy_function(14)}')
print(f'Test x = 13: {buggy_function(13)}')
print(f'Test x = 9: {buggy_function(9)}')
print(f'Test x = 8: {buggy_function(8)}')
print(f'Test x = 3.5: {buggy_function(3.5)}')

5. Debugging Your Code V

Debugging the Function factorial()

The function factorial() on the left computes the factorial of a number via the formula:

n!=n×(n−1)×(n−2)×⋯×1

However, when you try to run the script in the terminal via python Q5.py you will see that, due to the presence of bugs, the code outputs a wrong result.

Below, you have been provided with a simple debugging Tool: Code Visualizer. Click on the button Code Visualizer to launch it and debug your code. Feel free to resize the windows to see the complete output.

Problem

def factorial(n):
   counter = 0
   total = n
   while counter <= n:
       total *= (n-counter)
       counter += 1
   return total

print(factorial(3)) #should print 6

Solution

def factorial(n):
   counter = 1 
   total = 1 
   while counter <= n:
       total *= (counter)
       counter += 1
   return total

print(factorial(3)) #should print 6

Discussion 9.1: The Debugging Process

Have you debugged any programs before? From what you have learned in this module so far, what is the purpose of debugging, and how do you feel that it may be useful to you in future work? What would be a good strategy to find bugs quickly in your program using the debugging process?

In your post, answer the questions above and include an example of Python code that contains at least two syntax errors. Explain which steps you would consider taking to debug your code and fix the errors.

Discussion Prompt:

Read the statements posted by your peers. Engage with them by responding with thoughtful comments and questions to deepen the discussion.

Suggested Time: 45 minutes

Suggested Length: 250 words

This is a required activity and will count toward course completion.

Knowledge Check 9.1: GitHub Basics

Activity 9.1: Using GitHub

In this activity, you will be required to download the Jupyter Notebook file MIT.ipynb on your local machine and demonstrate your understanding of GitHub and its commands.

To complete the activity, perform the following steps:

  1. Using your personal GitHub account, create a repository named PCDE-Activity 9.1.
  2. Clone your repository to your local computer and add the Jupyter Notebook to it.
  3. Push the file to the remote repository.
  4. Open your local instance of Jupyter Notebook and edit the MIT.ipynb file to remove any errors. There are three obvious mistakes in the file. Make sure you fix them all. Add any additional file you may need to your repository to ensure that the content of the Notebook renders as expected.
  5. Commit and push your changes to the remote repository and ensure that everything works as expected.
  6. Optional: If you want to experiment further, select the README.md file in your remote repository and try to edit it so it displays Repository for Activity 9.1 as a Markdown header.
  7. Ensure that your repository is set to be public so your Learning Facilitator can mark your submission. Instructions about how to do so can be found at this link: How to Make a GitHub Repository Public. Submit the website URL to your GitHub repository.

Mini-Lesson 9.3: Setting Up Your GitHub Account for GitHub Pages

Most of this is covered in the GitHub Pages section of the GitHub notes.

Activity 9.2: GitHub Portfolio

In this activity, you will be required to upload the content of the repository “PCDE-Activity 9.1” that you created in Activity 9.1 to GitHub Pages.

To complete the activity, perform the following steps:

  1. Following the steps in Mini-Lesson 9.3, set up your GitHub account for GitHub Pages. At the end of this step, in your remote GitHub profile, you should have a repository named <your_username.github.io>.
  2. Ensure that your local copy of the “PCDE-Activity 9.1” repository is up to date on your local machine. You can do so by navigating to your local repository using your Terminal window (for Mac users) or Git Bash (for Windows users) and typing git pull.
  3. Select the README.md file in your remote repository and edit it so it displays “Repository for Activities 9.1 and 9.2” as a Markdown header.
  4. Navigate to “Settings” and enable the “PCDE-Activity 9.1” repository to be published on GitHub Pages, as demonstrated in Video 9.7. To accomplish this step, ensure that you select the main or root branch and select “Save”.
  5. Open a new browser window and verify that you can navigate to the following URL: https://<your_username>.github.io/PCDE-Activity-9.1. You may need to refresh the page to see the changes.
  6. Navigate to your remote GitHub repository, your_username.github.io, and edit the README.md file by adding the URL of the “PCDE-Activity 9.1” repository.
  7. Submit the website URL to your GitHub Pages repository.

Additional Details:

This is a required activity and counts toward course completion.

Knowledge Check 9.2: Python Classes

Knowledge Check 9.3: Python Advanced Functions

def add(*args):
  result = 0
  for x in args:
    result = result + x
  return result
print(add(30,15,10,5))

Knowledge Check 9.4: Python Decorators and Wrappers

def hi():
  return 'hi there!'
def wrapper(fun):
  text = 'hi from wrapper function'
  return f'{fun()} {text}!!!'
print(wrapper(hi))
def hello():
    return 'hi there!'
  def wrapper(fun):
    return f'{fun()} {`hi again`}!!!'
print(wrapper(hello))

References

Web Links

Note Links