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What is Dictionary

1. Definition
   1. Dictionaries: Dictionaries are built-in data structures that store collections of key-value pairs. Keys need to be immutable data types.

# Two methods to create a dictionary
sample_dictionary = {
    'name_key1' : 12, 
    'name_key2' : 'value'
}

sample_dictionary_2 = dict([('name', 'value'), ('price', 8.9), ('calories', 250), ('combo', ['french frise', 'Coke'])])

Access a value from a dictionary dictionary[key]

How to change/update value in a dictionary dictionary_name['key_name'] = 'new_value_name'

How to retrieve a value associated with a key get()

What is a view object?

What returns a view object with all the key-value pairs in the dictionary?

What removes all of the key-value pairs from the dictionary?

products = {
    'Laptop': 990,
    'Smartphone': 600,
    'Tablet': 250,
    'Headphones': 70,
}

for product in products.items():
    print(product)

('Laptop', 990)
('Smartphone', 600)
('Tablet', 250)
('Headphones', 70)

What is List

What is Set

Compare Dictionrary, List and Set

dictionrary = collection of key-value pairs list = ordered collection, allows duplicates set = unordered collection, does not allow duplicates

this_is_a_list = [1, 2, 2, 3] this_is_a_set = {1, 2, 3}

medical_record = ['name_1', 'name_2']

You can create an dictionary in a list

customer_infos = [
    {
        'patient_id': 'P1001',
        'first_name': 'Dann',
        'age': 22,
        'gender': 'Male',
        'purchase': ['milk toast', 'bread'],
        'last_visit_id': 'V2505',
    },
    {
        'patient_id': 'P1002',
        'first_name': 'Emilia',
        'age': 21,
        'gender': 'Female',
        'purchase': ['toast', 'white bread'],
        'last_visit_id': 'V2505',
    },
]

Practice Questions