urandom – Pseudo-random numbers

This module implements pseudo-random number generators.

All functions in this module should be used with positional arguments. Keyword arguments are not supported.

Basic random numbers

1100random fromto
randint(a, b) → int

Gets a random integer N satisfying a \leq N \leq b.

Parameters:

  • a (int) – Lowest value. This value is included in the range.

  • b (int) – Highest value. This value is included in the range.

Returns:

The random integer.

random() → float

Gets a random value x satisfying 0 \leq x < 1.

Returns:

The random value.

Random numbers from a range

getrandbits(k) → int

Gets a random integer N satisfying 0 \leq N < 2^{\text{k}}.

Parameters:

k (int) – How many bits to use for the result.

randrange(stop) → int
randrange(start, stop) → int
randrange(start, stop, step) → int

Returns a randomly selected element from range(start, stop, step).

For example, randrange(1, 7, 2) returns random numbers from 1 up to (but excluding) 7, in increments of 2. In other words, it returns 1, 3, or 5.

Parameters:

  • start (int) – Lowest value. Defaults to 0 if only one argument is given.

  • stop (int) – Highest value. This value is not included in the range.

  • step (int) – Increment between values. Defaults to 1 if only one or two arguments are given.

Returns:

The random number.

uniform(a, b) → float

Gets a random floating point value x satisfying a \leq x \leq b.

Parameters:

  • a (float) – Lowest value.

  • b (float) – Highest value.

Returns:

The random value.

Random elements from a sequence

choice(sequence) → Any

Gets a random element from a sequence such as a tuple or list.

Parameters:

sequence – Sequence from which to select a random element.

Returns:

The randomly selected element.

Raises:

IndexError – If the sequence is empty.

Updating the random seed

seed(value=None)

Initializes the random number generator.

This gets called when the module is imported, so normally you do not need to call this.

Parameters:

value – Seed value. When using None, the system timer will be used.