inf-bc-w06-python.md

Python 06: Functions, Dictionaries and Sets.

Introduction: This document presents learning steps for Python 06. In Python 06, you will learn dictionaries to collect keys and coresponding values. Moreover, you will learn more features of functions.

Note: Exercises of this learning path should be done using:

1. IDE: Using BRef-01: Chapter 19, Section: Integrated Development Environment PyCharm can be installed on your local machine.

Materials:

The activities are designed based on these following references:

• BRef-01: Book, Bill Lubanovic; "Introducing Python: Modern Computing in Simple Packages"; Available here
• ORef-01: Online Tutorial; Charles Severance; "Python for Everybody"; Available here
• ORef-02: Book, Brian Heinold; "A Practical Introduction to Python Programming" Available Online, Check here

Path:

Step-01: Dictionaries.

Goals:

After taking this step, you will be able to:
	1. interpret and implement Python programs with Python Dictionaries: creating, adding and modifying items,  extracting value(s), extracting key(s), deleting, pop and clear, iteration over dictionaries.

What to Learn?

1. Using BRef-01: Chapter 08 answer and experiment the following questions:
   1. What is a dictionary in Python and how can you create a dictionary?
   2. How can items be added/changed to/in a dictionary?
   3. How can you get the value of a given key?
   4. What are the behaviour of these functions: keys(), values(), items()?
   5. When can we use del, pop() and clear()? Experiment with some examples.
   6. How can one iterate over a dictionary?

Exercises:

1. Describe in your own words the difference between a dictionary and a tuple.

2. Create a new dictionary containing a key named FirstName with the value Larry, a key named LastName with the value Page. Print the last value from the dictionary.

3. Create a dictionary with the following pairs "brand": "Ford", "model": "Mustang", "year": 1964.

   • Print all the values from the distionary.
   • Print all the keys from the dictionary.
   • Print the length of the dictionary.
   • Add "color": "Red" and remove the pair with key = "year". Print keys and values separately.

4. Modify the code from the previous exercise so each value becomes a tuple containing two random numbers.

5. Provide your solutions to the exercises of ORef-01: Dictionary.

6. Design two exercises of your own. They should improve understanding topics of this step.

7. If you don't have PyCharm yet, install PyCharm on your working machine. Implement and run a simple Python program of your choice.

   • It is important to learn how to create a new Python program, how to configure interpreter and how to run the program. Where do you see the results?

8. Extra: Provide your solutions to the exercises of ORef-01: Dictionaries

---

Step-02: Functions (more).

Goals:

After taking this step, you will be able to:
	1. interpret and implement Python programs with Python functions: positional arguments, keyword arguments, parameters default values, docstrings.

What to Learn?

1. Using BRef-01: Chapter 09 answer and experiment the following questions:
   1. What are the positional arguments in Python? What about keyword arguments?
   2. How can one define default values for function parameters?
   3. What are Docstrings? How can they be helpful?

Exercises:

1. Describe in your own words what *args and **kwargs do.
2. Create a function that takes an *args of numbers as argument, which calculates the sum of all numbers and returns the result. Call the function and print the returned value.
3. Complete the given code below.

def count_passes(**kwargs):
   count = 0
   #Complete this function to count the number of passes

   return count
#
result = count_passes(math="Fail", science="Fail", history="Pass", english="Pass")
print(result)

5. Design two exercises of your own. They should improve understanding topics of this step.

6. Extra: Provide your solutions to the exercises of ORef-01: Functions

---

Step-03: Sets.

Goals:

After taking this step, you will be able to:
	1. interpret and implement Python programs with Python Sets: creating sets, difference between sets and lists and tuples, adding and removing elelemnts, membership operator, iteration over a set, basic operations between sets: intersection, union, difference and subset.

What to Learn?

1. Using BRef-01: Chapter 08 answer and experiment the following questions:
   1. What is a set in Python and how is it defined?
   2. How can one add/remove elements to/from a set?
   3. How can one iterate over a set?
   4. Assume two sets S1 and S2. How can one specify the following operations on S1 and S2 in Python:
      • Intersection of S1 and S2.
      • Union of S1 and S2.
      • Difference S1 and S2.
      • Is S1 a subset of S2 (or vice-versa)?

Exercises:

1. Describe in your own words the difference between a set and a tuple.

2. Describe in your own words the difference between a set and a list.

3. Create a set with and fill it with some values you can think of yourself. Print the length and the last value from the set.

4. Create a function which takes a dictionary as argument and returns a set created from the values of the given dictionary. Call the function and print all values from the returned set.

5. Create a set containing 5 letters x,y,q,z,u. Ask the user the input a letter. Check with if statement if the given letter is inside the set, print yes or no.

6. Design two exercises of your own. They should improve understanding topics of this step.

---

Learning Activities:

Code Analysis

1. Analyze the given code below without executing it. What will be the result of the program?

def do_something(*args, **kwargs):
   for i in args:
       for key, value in kwargs.items():
           if i == key:
               print(value)
#
#
do_something("a", "z", "d", "b", a=1, b=2, c=3, d=4)

2. Analyze the given code below without executing it. What will be the result of the program?

sfind = set('orihme')
schar = set('ichgo')
print("Step 1:")
for i in sfind:
   if i in schar:
       print(i)
#
print("Step 2:")
schar.update(sfind)
for i in schar:
   print(i)

3. Given the following code below. Explain in your own words what happens in this code. What are the keys in the dictionary?

import random
rdic = {}
for i in range(0,10):
   rdic[i] = random.randint(0,100)
for item in rdic.values():
   print(item)

Supporting Topics

Debugging

Introduction

Debugging is an essential process in software development that involves identifying, analyzing, and resolving issues or bugs within a program's code. It is a systematic approach to troubleshooting and improving the functionality and performance of software. Debugging typically involves identifying the root cause of a problem, using techniques such as step-by-step code execution, examining variable values, and analyzing error messages. By pinpointing and resolving issues, debugging helps ensure that software operates correctly, meets user requirements, and delivers a reliable and efficient user experience. Effective debugging skills are valuable for developers in maintaining and enhancing the quality of software systems.

Activity

Use the following code and debugging of your IDE and find the bug(s).

[todo: extend the instructions, inject a bug]

contacts = []

def add_contact(name, phone_numbers, email):
    contact = {
        'name': name,
        'phone_numbers': phone_numbers,
        'email': email
    }
    contacts.append(contact)

def search_contacts(keyword):
    return list(filter(lambda c: keyword.lower() in c['name'].lower(), contacts))

def delete_contact(name):
    for contact in contacts:
        if contact['name'].lower() == name.lower():
            contacts.remove(contact)

def update_contact(name, phone_numbers, email):
    for contact in contacts:
        if contact['name'].lower() == name.lower():
            contact['phone_numbers'] = phone_numbers
            contact['email'] = email
            break

def main():
    add_contact("John Doe", ["1234567890", "9876543210"], "john@example.com")
    add_contact("Jane Smith", ["5555555555"], "jane@example.com")
    add_contact("Bob Johnson", ["1111111111", "2222222222", "3333333333"], "bob@example.com")

    search_term = input("Enter a name to search: ")
    search_results = search_contacts(search_term)

    if search_results:
        print("Search Results:")
        for contact in search_results:
            print(f"Name: {contact['name']}")
            print("Phone Numbers:", ', '.join(contact['phone_numbers']))
            print(f"Email: {contact['email']}")
    else:
        print("No matching contacts found.")

    contact_name = input("Enter the name of the contact to delete: ")
    delete_contact(contact_name)
    print("Contact deleted successfully.")

    update_name = input("Enter the name of the contact to update: ")
    update_phone_numbers = input("Enter the new phone numbers (separated by commas): ").split(",")
    update_email = input("Enter the new email address: ")
    update_contact(update_name, update_phone_numbers, update_email)
    print("Contact updated successfully.")

main()