4 built-in data types

In Python, lists, sets, tuples, and dictionaries are used to store collections of data. Each has different properties and use cases.

• dictionary: an unordered, mutable collection that stores key-value pairs.
  It can contain different data types:
  ✅ Keys must be immutable (like strings, numbers, or tuples)
  ✅ values can be any data type (including other dictionaries)
  ✅ Dictionaries are defined using curly braces '{}', with key-value pairs separated by colons ':' and items separated by commas ','
  ✅ Dictionaries provide efficient lookups based on keys. You can access, add, modify, or remove items using their keys.
  
  Use dictionaries shen data needs to be stored as key-value pairs and when fast lookups are needed.

my_dict = {
    "name": "Alice",
    "age": 25,
    "city": "New York"
}

name = my_dict["name"]
age = my_dict["age"]
city = my_dict["city"]

my_dict['name'] # Alice

print(f"{name} is {age} years old and she lives in {city}") # Alice is 25 years old and she lives in New York.

name, age, height = employee
print(f"{name.title()} is {age} years old and {height}\" tall.") # John Doe is 30 years old and 5.9" tall.

# adding new key-value pairs
my_dict["country"] = "USA" # {'name': 'Alice', 'age': 25, 'city': 'New York', 'country': 'USA'}

# remove the key-value pair and return the value associated with the key
my_dict.pop("country") # USA

# delete key-value pair
del my_dict["city"] #
print(my_dict)
{'name': 'Alice', 'age': 25}

# loop through the dictionary
for key, value in my_dict.items():
  print(f"{key}: {value}") # name: Alice
                           # age: 25

print(my_dict.keys())  # Get all keys
print(my_dict.values())  # Get all values
print(my_dict.items())  # Get key-value pairs

# dict_keys(['name', 'age'])
# dict_values(['Alice', 25])
# dict_items([('name', 'Alice'), ('age', 25)])

# other examples
person = {
    "name": "Irene",
    "age": 32,
    "city": "New York",
    "occupation": "Software Engineer",
    "hobbies": ["gardening", "reading", "traveling"]
}

user_profile = {
    "username": "Irene32",
    "email": "irene@example.com",
    "preferences": {"language": "French", "theme": "dark mode"}
}

employees_list = [
    {"id": 1001, "name": "Alice Johnson", "position": "Software Engineer", "salary": 85000},
    {"id": 1002, "name": "Bob Smith", "position": "Software Engineer", "salary": 92000},
    {"id": 1003, "name": "Charlie Brown", "position": "Product Manager", "salary": 105000}
]

# look for software engineers
for employee in employees_list:
  if employee["position"] == "Software Engineer":
    print(f"{employee['name']} (ID: {employee['id']})") # Alice Johnson (ID: 1001)
                                                        # Bob Smith (ID: 1002)

for employee in employees_list:
  if employee["position"] == "Data Scientist":
    print(f"{employee['name']} (ID: {employee['id']})")
    data_scientists_found = True

if not data_scientists_found:
  print("No data scientists found.") # No data scientists found.