Generating random numbers

Generating random numbers

How to:

To generate random numbers in Elixir, you primarily use the :rand module which provides several functions for this purpose. Here is a quick guide to get you started:

First, ensure you seed the random number generator to initialize it with a unique starting point:


To generate a random integer within a range, use:

random_integer = :rand.uniform(10) # Generates a number between 1 and 10

For a random float between 0 and 1.0:

random_float = :rand.uniform()

You might need a more specific range for floats, which requires a bit more calculation:

min = 1.5
max = 5.5
random_float_range = min + (:rand.uniform() * (max - min))

Remember, these numbers are pseudo-random; they’re determined by the seed and algorithm but suffice for most applications.

Deep Dive

Elixir’s random number generation capabilities rely on Erlang’s :rand module, reflecting its heritage and close relationship with Erlang. The :rand module replaced the older :random module, offering improved algorithms for random number generation. It provides a variety of algorithms, the default being exsplus, but also supports others like exs64, exsl, and more, each with its trade-offs in terms of speed and randomness quality.

An interesting aspect of Elixir’s (and thus Erlang’s) random number generation is its handling of seeds. The system maintains separate seed states for each process, ensuring that concurrent processes don’t interfere with each other’s random number sequences. This is particularly useful in concurrent applications, ensuring predictability and reliability in distributed systems.

While the :rand module suffices for most use cases, applications requiring cryptographically secure random numbers should consider other options. The crypto module provides functions like crypto:strong_rand_bytes/1 that are designed to generate secure random data suitable for cryptographic purposes. These alternatives are essential for security-sensitive applications like token generation, encryption, and certain types of authentication mechanisms.