How do you create a dictionary in python?

Question 1

Key Concepts of a dict

Answer 1

A dictionary in Python contains a collection of key:value pairs.

Keys must be unique and are typically immutable, such as strings, numbers, or tuples.

Values can be of any type, and they can be duplicated.

Question 2

Creating a Dictionary

Answer 2

• You can use several methods to create a dictionary:

Literal Definition: Define key-value pairs within curly braces { }.

• From Key-Value Pairs: Use the dict() constructor or the {key: value} shorthand.
• Using the dict() Constructor: This can accept another dictionary, a sequence of key-value pairs, or named arguments.
• Comprehensions: This is a concise way to create dictionaries using a single line of code. (may need to find an example)
• zip() Function: This creates a dictionary by zipping two lists, where the first list corresponds to the keys, and the second to the values.

Question 3

zip() example

Answer 3

keys = ["a", "b", "c"]
values = [1, 2, 3]

zipped = zip(keys, values)
dict_from_zip = dict(zipped) # Result: {"a": 1, "b": 2, "c": 3}

Question 4

Key-Value Pairs example

Answer 4

# Using the `dict()` constructor
student_dict = dict([
    ("name", "John Doe"),
    ("age", 21),
    ("courses", ["Math", "Physics"])
])

Using the shorthand syntax
student_dict_short = {
    "name": "John Doe",
    "age": 21,
    "courses": ["Math", "Physics"]
}

Question 5

dict() Constructor example

Answer 5

# Sequence of key-value pairs
student_dict2 = dict(name="Jane Doe", age=22, courses=["Biology", "Chemistry"])

From another dictionary
student_dict_combined = dict(student, **student_dict2)