Passing an entire List to a Function

We are going to pass an entire list to a function.

    In [1]: numbers
    Out[1]: [10, 5, 3, 7, 4]

Defining a function which we going to pass the entire list to.  This function multiplies each of the list's element by 2.
    In [2]: def modify_elements(items):
    ...:     for i in range(len(items)):
    ...:         items[i] *= 2
    ...:

    In [3]: modify_elements(numbers)

    In [4]: numbers
    Out[4]: [20, 10, 6, 14, 8]

    In [5]:

Function modify_elemens' items parameter receives a reference to the original list, so the statement in the loop's suite modifies each element in the original list object.

Python built-in Function Enumerate

Using a built-in function Enumerate in Python to access an element's INDEX and VALUE.

Create a list with integers

    In [1]: numbers = [10,5,3,7,4]

    In [2]: type(numbers)
    Out[2]: list

    In [3]:

Apply built-in function Enumerate to numbers

    In [3]: new_numbers = enumerate(numbers)

    In [4]: new_numbers
    Out[4]: <enumerate at 0x233d866db80>

Convert it to list format|

    In [6]: list(new_numbers)
    Out[6]: [(0, 10), (1, 5), (2, 3), (3, 7), (4, 4)]

    In [7]:

Going to create a simple bar chart using the value in numbers

    In [1]: numbers = [10,5,3,7,4]

    In [2]: for index, value in enumerate(numbers):

       ...:     print(f'{index:>8}{value:>8}  {"|" * value}')
       ...:

        0      10  ||||||||||
        1       5  |||||
        2       3  |||
        3       7  |||||||
        4       4  ||||

      In [3]:

Remove duplicate from Python list

 This post is to show how to remove duplicate entries in a List.

Create an empty list and we name it new_list.

In [1]: new_list = []

We iterate a range of integers and assign it to this new_list.

In [2]: for items in range(1,6):
   ...:     new_list += [items]
   ...:

Show what is inside this list

In [3]: new_list
Out[3]: [1, 2, 3, 4, 5]

We iterate another range of integers where there are duplicates into the same new_list

In [4]: for new_items in range(7):
   ...:     new_list += [new_items]
   ...:

This show the new_list has duplicate entries

In [5]: new_list
Out[5]: [1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6]

Create a dictionary, using the List items as keys. This will automatically remove any duplicates because dictionaries cannot have duplicate keys.
Then, convert the dictionary back into a list.

In [6]: new_list = list(dict.fromkeys(new_list))

In [7]: new_list
Out[7]: [1, 2, 3, 4, 5, 0, 6]

In [8]:

Python 3 - Nested Control Statement

Learning nested control statement in Python 3.
Taking notes on what I missed during the learning process.

1.  Remember to add comma when displaying str and variable together.

     Example: print ('Passed: ',(pass_counter))
2.  Learn to use nested control such as if...else within the for loop.

3.  Use for statement and the range function is appropriate when we know in advance that there are 10 exam results.

# fig03_03.py
"""Using nested control statements to analyze examination results."""

# initialize variables
pass_counter = 0 # number of passes
fail_counter = 0 # number of failures

# process 10 students
# exam_grades = int(input('Enter 1 for pass or 2 for fail: '))
for student in range(10):
    # get one exam result
    result = int(input('Enter result (1=pass, 2=fail): '))
    
    if result == 1:
        pass_counter += 1
    else:
        fail_counter += 1

# termination phase
print('Passed: ',(pass_counter))
print('Failed: ',(fail_counter))
    
if pass_counter > 8:
    print ('Bonus to instructor')