How can I randomly select one element from a vector or array?

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I have a vector where the element is a (String, String). How can I randomly pick one of these elements?

You want the rand crate, specifically the choose method.

use rand::seq::SliceRandom; // 0.7.2

fn main() {
    let vs = vec![0, 1, 2, 3, 4];
    println!("{:?}", vs.choose(&mut rand::thread_rng()));
}

Randomly select an element from a vector satisfying a condition , You want the rand crate, specifically the choose method. use rand::seq:: SliceRandom; // 0.6.5 fn main() { let vs = vec![0, 1, 2, 3, 4]; println!("{:?}� I am looking to select n random elements from a vector, but none of the elements can be the same. for example x=[1 1 1 2 3 4 4 4 5 6 7 7], I want to select 4 random

Using choose_multiple:

use rand::seq::SliceRandom; // 0.7.2

fn main() {
    let samples = vec!["hi", "this", "is", "a", "test!"];
    let sample: Vec<_> = samples
        .choose_multiple(&mut rand::thread_rng(), 1)
        .collect();
    println!("{:?}", sample);
}

randomly select elements of an array - MATLAB Answers, create an intermediate array with all elements of X satisfying your condition; select a single element from that. You can combine the two steps in a� choose elements from array randomly. Learn more about choose element

Another choice for weighted sampling that is already included in the rand crate is WeightedIndex, which has an example:

use rand::prelude::*;
use rand::distributions::WeightedIndex;

let choices = ['a', 'b', 'c'];
let weights = [2,   1,   1];
let dist = WeightedIndex::new(&weights).unwrap();
let mut rng = thread_rng();
for _ in 0..100 {
    // 50% chance to print 'a', 25% chance to print 'b', 25% chance to print 'c'
    println!("{}", choices[dist.sample(&mut rng)]);
}

let items = [('a', 0), ('b', 3), ('c', 7)];
let dist2 = WeightedIndex::new(items.iter().map(|item| item.1)).unwrap();
for _ in 0..100 {
    // 0% chance to print 'a', 30% chance to print 'b', 70% chance to print 'c'
    println!("{}", items[dist2.sample(&mut rng)].0);
}

Pick random element, If I want to find a random element in one row of a matrix, Could you help me How can I do? For example I want to select a random element in last row of a matrix. Copy to Clipboard. If it is just about how to extract an element randomly, you can try by random indexing, you can try the following for the given vector: x = [0 0 0 1 1 1 2 2 2 2]; len = length (x); for i = 1:length (x) y = randi ( [1 len],1,1); % generates random number for indexing. disp (x (y));

If you want to pick more than one element, than the crate random_choice may be the right for you:

extern crate random_choice;
use self::random_choice::random_choice;

fn main() {
    let mut samples = vec!["hi", "this", "is", "a", "test!"];
    let weights: Vec<f64> = vec![5.6, 7.8, 9.7, 1.1, 2.0];

    let number_choices = 100;
    let choices = random_choice().random_choice_f64(&samples, &weights, number_choices);

    for choice in choices {
        print!("{}, ", choice);
    }
}

Python random.choice() to choose random element from list, String , pick a random element from an array of strings # OP PICKRANDOM int main( ) { std::vector<int> numbers { 11 , 88 , -5 , 13 , 4 , 121 , 77 , 2 } ; Randomly select multiple choices from the list As you know, the random.choice () function only returns a single item from a list. If you want to randomly select more than one item from a list or set, I’d recommend using random.sample () or random.choice s () instead.

If you also want to remove the chosen element, here's one way to do that (using the rand crate):

let mut vec = vec![0,1,2,3,4,5,6,7,8,9];

let index = (rand::random::<f32>() * vec.len() as f32).floor() as usize;
let value = vec.remove( index );

println!("index: {} value: {}", index, value);
println!("{:?}", vec);

Rust Playground

remove(index) removes that value at index (shifting all the elements after it to the left) and the returns the value that was at index (docs).

How to select a random element from array in JavaScript , Use random module choice() function to randomly select an item a multidimensional array; Choose the same element from the list every time. randomly select elements of an array. Follow 678 views (last 30 days) If I want to find a random element in one row of a matrix, Could you help me How can I do?

How can I randomly select element from a vector or array in rust , How to select a random element from array in JavaScript ? Use Math. random() function to get the random number between(0-1, 1 exclusive). Multiply it by the array length to get the numbers between(0-arrayLength). Use Math. floor() to get the index ranging from(0 to arrayLength-1). Many times looking in the library can be more helpful. Getting the documentation for the random module would have worked. It does take some time to know where to look, but for anything involving "random" check the random module first. – Kathy Van Stone Jun 29 '09 at 15:18

numpy.random.choice — NumPy v1.10 Manual, If I have a vector or array in rust, how can I randomly pick one element out, and the element is a struct. string random; for(int i = 0; i < 3; i++) { random = choices[rand() % 5]; } return random; To produce the 3 results, you need to return a vector of string like

Random Numbers � The Julia Language, If an ndarray, a random sample is generated from its elements. if a or p are not 1-dimensional, if a is an array-like of size 0, if p is not a vector of probabilities,�

Comments
  • what an over-complicated way to get a random element :(
  • I'd disagree. The only differences with this approach and other languages are the need to put the trait in scope and manually needing to specify where the rng state comes from. Perhaps a tad more explicit than usual, but I find it okay.