:mod:`random` -- generate random numbers ======================================== .. module:: random :synopsis: random numbers This module implements a pseudo-random number generator (PRNG). |see_cpython_module| :mod:`python:random` . .. note:: The following notation is used for intervals: - () are open interval brackets and do not include their endpoints. For example, (0, 1) means greater than 0 and less than 1. In set notation: (0, 1) = {x | 0 < x < 1}. - [] are closed interval brackets which include all their limit points. For example, [0, 1] means greater than or equal to 0 and less than or equal to 1. In set notation: [0, 1] = {x | 0 <= x <= 1}. .. note:: The :func:`randrange`, :func:`randint` and :func:`choice` functions are only available if the ``MICROPY_PY_URANDOM_EXTRA_FUNCS`` configuration option is enabled. Functions for integers ---------------------- .. function:: getrandbits(n) Return an integer with *n* random bits (0 <= n <= 32). .. function:: randint(a, b) Return a random integer in the range [*a*, *b*]. .. function:: randrange(stop) randrange(start, stop) randrange(start, stop[, step]) The first form returns a random integer from the range [0, *stop*). The second form returns a random integer from the range [*start*, *stop*). The third form returns a random integer from the range [*start*, *stop*) in steps of *step*. For instance, calling ``randrange(1, 10, 2)`` will return odd numbers between 1 and 9 inclusive. Functions for floats -------------------- .. function:: random() Return a random floating point number in the range [0.0, 1.0). .. function:: uniform(a, b) Return a random floating point number N such that *a* <= N <= *b* for *a* <= *b*, and *b* <= N <= *a* for *b* < *a*. Other Functions --------------- .. function:: seed(n=None, /) Initialise the random number generator module with the seed *n* which should be an integer. When no argument (or ``None``) is passed in it will (if supported by the port) initialise the PRNG with a true random number (usually a hardware generated random number). The ``None`` case only works if ``MICROPY_PY_URANDOM_SEED_INIT_FUNC`` is enabled by the port, otherwise it raises ``ValueError``. .. function:: choice(sequence) Chooses and returns one item at random from *sequence* (tuple, list or any object that supports the subscript operation).