Dictionaries, OOP & Classes

A dictionary (dict) is an unordered collection of key–value pairs. Each key acts as a named property, and every key maps to exactly one value. Dictionaries are useful whenever you want to group related pieces of data under meaningful names rather than positional indices.

Creating a dictionary:

course_info = {
    'name': 'Applied Data Science',
    'university': 'FAU',
    'term': 'summer term'
}

Accessing a value by key:

print(course_info['university'])  # → FAU

Iterating over all entries:

print(course_info.keys())    # dict_keys(['name', 'university', 'term'])
print(course_info.values())  # dict_values(['Applied Data Science', 'FAU', 'summer term'])
print(course_info.items())   # pairs of (key, value)

The methods .keys(), .values(), and .items() return view objects — they reflect the current state of the dictionary at all times.