gen-element: Random Sample Generation

In hedgehog: Property-Based Testing

Description

Generators which sample from a list or produce random integer samples. Both single sample, with gen.element; and multi-sample, with gen.sample and gen.subsequence are supported; while gen.choice is used to choose from generators instead of examples.

Usage

gen.element(x, prob = NULL)

gen.int(n, prob = NULL)

gen.choice(..., prob = NULL)

gen.subsequence(x)

gen.sample(x, size, replace = FALSE, prob = NULL)

gen.sample.int(n, size, replace = FALSE, prob = NULL)

Arguments

x	a list or vector to sample an element from.
prob	a vector of probability weights for obtaining the elements of the vector being sampled.
n	the number which is the maximum integer sampled from.
...	generators to sample from
size	a non-negative integer or a generator of one, giving the number of items to choose.
replace	Should sampling be with replacement?

Details

These generators implement shrinking.

Value

gen.element returns an item from the list or vector; gen.int, an integer up to the value n; gen.choice, a value from one of given selected generators; gen.subsequence an ordered subsequence from the input sequence; and gen.sample a list or vector (depending on the input) of the inputs.

For gen.element and gen.choice, shrinking will move towards the first item; gen.int will shrink to 1; gen.subsequence will shrink the list towards being empty; and gen.sample will shrink towards the original list order.

Examples

gen.element(1:10)   # a number
gen.element(c(TRUE,FALSE)) # a boolean
gen.int(10) # a number up to 10
gen.choice(gen.element(1:10), gen.element(letters))
gen.choice(NaN, Inf, gen.unif(-10, 10), prob = c(1,1,10))
gen.subsequence(1:10)

hedgehog documentation built on May 2, 2019, 11:27 a.m.