random – generate random numbers

This module implements a pseudo-random number generator (PRNG).

This module implements a subset of the corresponding CPython module, as described below. For more information, refer to the original CPython documentation: random .


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}.


The randrange(), randint() and choice() functions are only available if the MICROPY_PY_URANDOM_EXTRA_FUNCS configuration option is enabled.

Functions for integers


Return an integer with n random bits (0 <= n <= 32).

random.randint(a, b)

Return a random integer in the range [a, b].

random.randrange(start, stop)
random.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


Return a random floating point number in the range [0.0, 1.0).

random.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

random.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.


Chooses and returns one item at random from sequence (tuple, list or any object that supports the subscript operation).