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60. The init Constructor

1. Introduction​

The __init__ method is a special constructor in Python classes.
It runs automatically when a new object is created.

2. Basic Example​

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

p = Person("Alice", 30)
print(p.name, p.age)

3. Default Values​

class Person:
    def __init__(self, name, age=18):
        self.name = name
        self.age = age

p = Person("Bob")
print(p.name, p.age)  # Bob 18

4. Why Use init?​

  • Initialize attributes.
  • Set default states.
  • Validate input during object creation.

5. Best Practices​

  • Keep __init__ simple.
  • Don’t overload it with logic — use helper methods.

6. Next Steps​

✅ You now understand the __init__ constructor.
Next: Instance vs class variables.