all Python 3randomfunction

random.getrandbits

bits and bytes

An integer of k random bits (0 <= result < 2**k); it draws on the core generator, so it is reproducible under a fixed seed.

Syntax

random.getrandbits(k)

The engine underneath is the Mersenne Twister: observe enough output and its internal state can be reconstructed, so passwords, tokens and keys belong to secrets.randbits() or os.urandom() instead. A negative k raises ValueError, while k=0 is legal and always yields 0.

Examples

# Python 3.9+
import random
random.seed(0)
print(random.getrandbits(8))   # → 216
print(0 <= random.getrandbits(4) < 16)   # → True
print(len(f'{random.getrandbits(128):032x}'))   # → 32
print(random.getrandbits(0))   # → 0
print(random.getrandbits(-1))   # → ValueError

See also

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