Added Python encapsulation file

content/python/concepts/encapsulation/encapsulation.md

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+# Encapsulation in Python
+
+Encapsulation is one of the fundamental principles of Object-Oriented Programming (OOP). It refers to the bundling of data (attributes) and the methods (functions) that operate on the data into a single unit, typically a class. In Python, encapsulation helps restrict access to certain components of an object to ensure better modularity and protection against unintended interference or misuse.
+
+---
+
+## Key Concepts
+
+### 1. **Access Modifiers in Python**
+Python does not have strict access modifiers like other languages (e.g., `private`, `protected`, `public`). Instead, it relies on naming conventions:
+
+| Modifier | Syntax | Access Level |
+|----------|--------|--------------|
+| Public   | `var`  | Accessible from anywhere |
+| Protected| `_var` | Should not be accessed outside the class or subclass |
+| Private  | `__var`| Name mangled to prevent direct access from outside |
+
+### 2. **Why Use Encapsulation?**
+- Prevents external code from directly modifying object data
+- Increases code modularity and reusability
+- Helps in debugging and maintenance
+- Allows controlled access through getter and setter methods
+
+---
+
+## Example of Encapsulation in Python
+
+```python
+class BankAccount:
+    def __init__(self, owner, balance=0):
+        self.owner = owner        # public attribute
+        self.__balance = balance  # private attribute
+
+    def deposit(self, amount):
+        if amount > 0:
+            self.__balance += amount
+            print(f"Deposited {amount}, new balance: {self.__balance}")
+        else:
+            print("Deposit amount must be positive")
+
+    def withdraw(self, amount):
+        if 0 < amount <= self.__balance:
+            self.__balance -= amount
+            print(f"Withdrew {amount}, new balance: {self.__balance}")
+        else:
+            print("Insufficient funds or invalid amount")
+
+    def get_balance(self):
+        return self.__balance
+```
+
+---
+
+## Accessing Private Variables
+Although Python does not enforce access restriction, private variables can still be accessed using *name mangling*:
+
+```python
+account = BankAccount("Alice", 1000)
+print(account.get_balance())       # Proper access
+print(account._BankAccount__balance)  # Not recommended, but possible
+```
+
+---
+
+## Best Practices
+- Use `__` for attributes that should not be accessed directly
+- Provide `getter` and `setter` methods for controlled access
+- Keep class attributes private unless there's a good reason to expose them
+
+---
+
+*Last updated: 2025-05-01*