inf-bc-w05-python.md

Python 05: Functions, Lists and Tuples.

Introduction: This document presents learning steps for Python 05. In Python 05, you will learn how to build a sequence structure using basic data types. Moreover, you will learn more features of functions.

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

1. IDE: Using online resources Visual Studio Code 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

Path:

Step-01: Tuples.

Goals:

After taking this step, you will be able to:
	1. interpret and implement Python programs using tuples: creating, unpacking, modifying, combining two tuples, iterating over a tuple.

What to Learn?

1. Using BRef-01: Chapter 07 answer and experiment the following questions:
   1. What is a tuple in Python and how is it defined?
   2. How can one combine and compare two (or more) tuples?
   3. How can one iterate over the elements of a tuple?
   4. How is a tuple modified?

Exercises:

1. You can create a tuple with mixed types in it, for example texts and numbers. Can you think of a advantage and a disadvantage of doing this? Implement your example.
2. Create a tuple with three numbers in it. Unpack the tuple into three different variables. Print the last one.
3. Create a tuple with two numbers in it, create a second tuple with two texts in it. Add them together into a new tuple. Print the new tuple.
4. Create a tuple with three numbers in it. Use a for loop to iterate over each value. Multiply each value by 2 and print each result.
5. Create a function that returns a tuple containing three texts. Call the function. Unpack the tuple into variables. Print the variables.
6. Design two exercises of your own. They should improve understanding topics of this step.

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Step-02: Lists.

Goals:

After taking this step, you will be able to:
	1. interpret and implement Python programs using lists: defining, offset, slicing, adding new element, modifying an element.

What to Learn?

1. Using BRef-01: Chapter 07 answer and experiment the following questions:
   1. What is a list in Python and how is it defined?
   2. What is the result of split() on a string?
   3. There are two ways to get items from a list: offset and slice. What are the pros / cons of each? Experiment with some examples.
   4. How can you add new elements to a list?
   5. How can you modify elements of a list?
   6. How can one iterate over the elements of a list?
   7. Mutability is one of the main differences between a tuple and a list. Elaborate this with some example.

Exercises:

1. Define a list of integers representing scores of a game. Write a program that prints out maximum and minimum of the scores.
2. Extend your program from the previous exercise such that it prints two largest and two smallest elements of the scores.
3. Write a program that asks the user to enter a list of integers. Do the following:
   • Print the total number of items in the list.
   • Print the last item in the list.
   • Print the list in reverse order.
   • Print Yes if the list contains a 5 and No otherwise.
   • Print the number of fives in the list.
   • Remove the first and last items from the list, sort the remaining items, and print the result.
   • Print how many integers in the list are less than 5.
4. Write a program that generates a list of 20 random numbers between 1 and 100.
   • Print the list.
   • Print the average of the elements in the list.
   • Print the largest and smallest values in the list.
   • Print the second largest and second smallest entries in the list
   • Print how many even numbers are in the list.
5. Start with the list [8,9,10]. Do the following:
   • Set the second entry (index 1) to 17
   • Add 4,5, and 6 to the end of the list
   • Remove the first entry from the list
   • Sort the list
   • Double the list
   • Insert 25 at index 3
   • The final list should equal [4,5,6,25,10,17,4,5,6,10,17]
6. Create the following lists using a loop.
   • A list consisting of the integers 0 through 49
   • A list containing the squares of the integers 1 through 50.
   • The list ['a','bb','ccc','dddd', . . . ] that ends with 26 copies of the letter z.
7. Write a program that takes any two lists L and M of the same size and adds their elements together to form a new list N whose elements are sums of the corresponding elements in L and M. For instance, if L=[3,1,4] and M=[1,5,9], then N should equal [4,6,13].
8. Design two exercises of your own. They should improve understanding topics of this step.

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Step-03: 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)

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

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

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Code Analysis

1. Analyze the given codes below without executing them. What will be the result of the programs?

a_tuple = ('Never', 'gonna', 'give', 'you', 'up')
counter = 0
for x in a_tuple:
    if x[0] ==  'g':
        counter = counter + 1
    else:
        counter = counter + 2
print(counter)

def do_something(x):
    rtuple = x,
    for i in range(2,11):
        rtuple = rtuple + ((x*i),)
    return rtuple
print(do_something(6))

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)

def process_strings(strings):
    processed_strings = []
    for string in strings:
        processed_string = ""
        for char in reversed(string):
            processed_string += char
        processed_strings.append(processed_string)
    return processed_strings

def main():
    names = ["Alice", "Bob", "Charlie", "Dave"]
    processed_names = process_strings(names)
    for name in processed_names:
        print(name)

main()