What is caching in Python?

Question

Accepted Answer

**@lru_cache** — caching function results.

```python
from functools import lru_cache, cache

@lru_cache(maxsize=128)
def fibonacci(n):
    if n < 2:
        return n
    return fibonacci(n-1) + fibonacci(n-2)

fibonacci(100)  # Fast!

# Basic cache (Python 3.9+)
@cache
def expensive_function(x):
    return x ** 2

# Custom cache
from cachetools import TTLCache

cache = TTLCache(maxsize=100, ttl=300)  # 5 minutes

@cached(cache=cache)
def get_user(user_id):
    return db.get_user(user_id)

# Statistics
print(fibonacci.cache_info())
fibonacci.cache_clear()  # Clear

# Django cache
from django.core.cache import cache

def get_products():
    data = cache.get("products")
    if data is None:
        data = Product.objects.all()
        cache.set("products", data, 300)  # 5 minutes
    return data
```

**Strategies:**
- LRU (Least Recently Used).
- TTL (Time To Live).
- LFU (Least Frequently Used).

Python: What is caching in Python?