docs/library/random.rst
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_RANDOM_EXTRA_FUNCS configuration option is
enabled.
.. 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.
.. 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*.
.. 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_RANDOM_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).