Chapter 1: Introduction to Basic Python Programming - Variables and Datatypes

Excercise 1 :

• Create a variable monthly_savings, equal to 10 and num_months, equal to 4.

• Multiply monthly_savings by num_months and assign it to new_savings.

• Print the value of new_savings.

  

  In Python, semicolons at the end of a statement are optional and usually omitted unless multiple statements are written on a single line.

Excercise 2:

🔹 1. Dynamic Typing

• Python is dynamically typed, meaning you don’t need to declare data types.

    x = 5     # int
    x = "Hi"  # now it's a str!
  

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🔹 2. Mutability

🧠 Why it matters: Mutable types can be changed after creation, affecting performance and behavior when passed into functions.

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🔹 3. Type Conversion

• You can convert between types easily:

    int("5")         # 5
    str(100)         # "100"
    list("hello")    # ['h', 'e', 'l', 'l', 'o']
  

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🔹 4. Memory Efficiency

• tuple is more memory-efficient than list.

• Use frozenset when you don’t want the set to change.

• range() is memory-efficient for large loops as it generates numbers on demand (lazy evaluation).

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🔹 5. NoneType Usage

• None is used for default values in functions or to represent “no value”.

    def greet(name=None):
        if name:
            print("Hi", name)
        else:
            print("Hi there!")
  

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🔹 6. Identity vs Equality

• Use == to compare values, is to check identity (same memory location).

    a = [1, 2]
    b = a
    a == b  # True
    a is b  # True
  

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🔹 7. Custom Types

• You can define your own data types using class:

    class Car:
        def __init__(self, brand):
            self.brand = brand