Cookbook ideas for the rand crate

[brson]

We already have 4 examples:

• Generate random floating point numbers
• Generate random numbers within a range  
• Generate random numbers with normal distribution
• Generate random values of a custom type
• Create random passwords from a set of allowed characters
• TODO: review 0.5 API, suggest new recipes

So it's not obvious we need more. But here's an opportunity to reevaluate the set we've got and brainstorm about it.

[Phaiax]

Similar to the range example: Create random passwords from a set of allowed characters.

[convoliution]

How about an example of creating a specified-length vector of random numbers out of rng.gen_iter()?

edit: I realize a bit late that with the current rand API, it might be more practical to push values into the vector in a for loop, especially if you need a particular range or distribution.

[budziq]

@mykalu

it might be more practical to push values into the vector in a for loop, expecially if you need a particular range or distribution

Fair points. To be honest rand requires a major rewrite to make it really pleasant to use.
It all depends on what the user needs, (ie. If they do not care about the distribution) then gen_iter approach might be viable. If one despises for loops one can always build custom iterator (~4-5 additional lines) or use hacky range mapping approach ;)

    let mut rng = rand::thread_rng();
    // mean 2, standard deviation 3:
    let normal = Normal::new(2.0, 3.0);
    let v: Vec<_> = (0..10).map(|_| normal.ind_sample(&mut rng)).collect();

[AndyGauge]

Rand is going through an overhaul. 0.5-pre 1 just came out. I would like to revisit this issue once 0.5 ships and evaluate adding recipes later.

[AndyGauge]

I read the 0.5 Changelog and the stuff they added was great, but not really helpful to a wide audience. Most of the changes were to support true randomness required for a security perspective. I'm not sure there's a lot of value to a wide audience for this. @pitdicker did a good job in #391 to update the API. I think the cookbook has a good sample of Rand usage.