Untitled

list.py

# Creating and printing lists
def my_list():
    dog_breeds = ['corgi', 'labrador', 'poodle', 'jack russell']
    print(dog_breeds)  # ['corgi', 'labrador', 'poodle', 'jack russell']

    list_out_of_string = list('danger!')
    print(list_out_of_string)  # ['d', 'a', 'n', 'g', 'e', 'r', '!']

    # list_out_of_integer = list(235)  # TypeError: 'int' object is not iterable

    # a string is an example of an iterable object
    # an integer is an example of a non-iterable object
    # A list itself is also an iterable object.


# Features of lists:
# Lists can store duplicate values as many times as needed.
# They can contain different types of elements
def features_of_lists():
    on_off_list = ['on', 'off', 'on', 'off', 'on']
    print(on_off_list)  # ['on', 'off', 'on', 'off', 'on']

    different_objects = ['a', 1, 'b', 2, [1, 2, 3]]

    languages = ['Python', 'JAVA', 'C++', 'JavaScript']

    # Append new language to the list
    languages.append('Ruby')
    print('List of programming languages: ' + ', '.join(languages))  # List of programming languages: Python, JAVA, C++, JavaScript, Ruby

    # Remove the first occurrence of a value
    on_off_list.remove('off')
    print(on_off_list)  # ['on', 'on', 'off', 'on']


def length_of_list():
    numbers = [1, 2, 3, 4, 5]
    print(len(numbers))  # 5

    empty_list = list()
    empty_list = []
    print(len(empty_list))  # 0

    single_element_list = ['danger!']
    print(len(single_element_list))  # 1

    multi_elements_list = list('danger!')
    print(len(multi_elements_list))  # 7


def reading_input():
    read = list(input())  # 1 2 3 string
    print(read)  # ['1', ' ', '2', ' ', '3', ' ', 's', 't', 'r', 'i', 'n', 'g']


my_list()
features_of_lists()
reading_input()

#########################################################

indexes.py

# Positionally ordered collections of elements are usually called sequences, and both lists and strings belong to them
# Indexes are used to access elements within a sequence

def indexes_of_elements():
    colors = ['red', 'green', 'blue']
    first_elem = colors[0]  # 'red'
    second_elem = colors[1]  # 'green'
    third_elem = colors[2]  # 'blue'

    pet = "cat"
    first_char = pet[0]  # 'c'
    second_char = pet[1]  # 'a'
    third_char = pet[2]  # 't'


def potential_pitfalls():
    colors = ['red', 'green', 'blue']
    pet = "cat"

    print(colors[3])  # IndexError: list index out of range
    print(pet[3])  # IndexError: string index out of range

    colors[1] = 'white'
    print(colors)  # ['red', 'white', 'blue']

    pet[0] = "b"  # TypeError: 'str' object does not support item assignment


def negative_indexes():
    colors = ['red', 'green', 'blue']
    last_elem = colors[-1]  # 'blue'
    second_elem = colors[-2]  # 'green'
    first_elem = colors[-3]  # 'red'

    pet = "cat"
    last_char = pet[-1]  # 't'
    second_char = pet[-2]  # 'a'
    first_char = pet[-3]  # 'c'

    # 0    1      ... len-2 len-1
    # -len -len+1 ... -2    -1