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