How does memory management work in Python?

Question

Accepted Answer

Python uses **automatic memory management** via reference counting and garbage collection.

**Reference counting:**
- Each object has a reference counter.
- When counter reaches 0 — object is deleted.
- `sys.getrefcount(obj)` — check references.

```python
import sys

a = [1, 2, 3]
print(sys.getrefcount(a))  # 2 (a + argument)

b = a  # New reference
print(sys.getrefcount(a))  # 3

del a  # Delete reference
print(sys.getrefcount(b))  # 2
```

**Garbage Collection (GC):**
- Handles **circular references**.
- `gc.collect()` — manual run.
- `gc.garbage` — objects that cannot be deleted.

```python
import gc

# Circular reference
a = []
b = []
a.append(b)
b.append(a)

del a, b
gc.collect()  # Cleanup
```

**Memory pools:**
- Small objects (< 512 bytes) — Pymalloc allocator.
- Large objects — system malloc.

Python: How does memory management work in Python?