# Keys

> USearch for Python

Keys are 128 bits wide and render as lowercase dashed UUIDs.
Integer keys sit in the low eight bytes, so `Key(42)` prints as `00000000-0000-0000-0000-00000000002a`, and keys need not be unique: several entries may share one, and `count` reports how many.

```python
import uuid
from usearch import Key

Key(42)  # from an integer
Key("00000000-0000-0000-0000-00000000002a")  # from the dashed rendering
Key(uuid.uuid4())  # from a `uuid.UUID`
```

A key equals and hashes as the integer or `uuid.UUID` it reads as, never as the text or bytes it parses from, and pickles as its sixteen bytes.
No NumPy dtype expresses a 128-bit integer, so batch keys travel in both directions as big-endian sixteen-byte rows, an `(N, 16)` buffer of `uint8`.
`usearch.keys` carries `integers_to_keys` and `keys_to_integers` for the common case where keys really are just entry numbers.

`from usearch import Key`

## Key

A 128-bit entry identity, rendered as a lowercase dashed UUID.

```python
class Key
```

## Key

```python
Key(value: _KeyLike = 0, /)
```

## bytes

The sixteen identity bytes, most significant first.

```python
bytes: bytes
```