Function rand::seq::sample_indices

pub fn sample_indices<R: ?Sized>(
    rng: &mut R, 
    length: usize, 
    amount: usize
) -> Vec<usize> where
    R: Rng, 

Randomly sample exactly amount indices from 0..length.

The values are non-repeating and in random order.

This implementation uses O(amount) time and memory.

This method is used internally by the slice sampling methods, but it can sometimes be useful to have the indices themselves so this is provided as an alternative.

Panics if amount > length