Function malachite_base::strings::random::random_strings_using_chars

source · [−]

pub fn random_strings_using_chars<I: Iterator<Item = char>>(
    seed: Seed, 
    cs_gen: &dyn Fn(Seed) -> I, 
    mean_length_numerator: u64, 
    mean_length_denominator: u64
) -> StringsFromCharVecs<RandomVecs<char, GeometricRandomNaturalValues<u64>, I>>ⓘNotable traits for StringsFromCharVecs<I>impl<I: Iterator<Item = Vec<char>>> Iterator for StringsFromCharVecs<I>    type Item = String;

Expand description

Generates random Strings using chars from an iterator.

The lengths of the Strings are sampled from a geometric distribution with a specified mean $m$, equal to mean_length_numerator / mean_length_denominator. $m$ must be greater than 0.

$$ P((c_0, c_1, \ldots, c_{n-1})) = \frac{m^n}{(m+1)^{n+1}}\prod_{i=0}^{n-1}P(c_i). $$

The iterators produced by cs_gen must be infinite.

Panics

Panics if mean_length_numerator or mean_length_denominator are zero, or, if after being reduced to lowest terms, their sum is greater than or equal to $2^{64}$.

Examples

extern crate itertools;

use itertools::Itertools;
use malachite_base::chars::random::random_char_inclusive_range;
use malachite_base::random::EXAMPLE_SEED;
use malachite_base::strings::random::random_strings_using_chars;

let ss = random_strings_using_chars(
    EXAMPLE_SEED,
    &|seed| random_char_inclusive_range(seed, 'x', 'z'),
    4,
    1,
)
.take(10)
.collect_vec();
assert_eq!(
    ss.iter().map(|cs| cs.as_str()).collect_vec().as_slice(),
    &["", "yyyyzxxxzxzxzx", "zzzy", "xzzx", "y", "", "zyzxz", "zy", "zyyx", ""]
);