Effacer les filtres
Effacer les filtres

primes function

3 vues (au cours des 30 derniers jours)
Sean Smith
Sean Smith le 18 Sep 2011
Is there a way to use the prime function to find the prime numbers between two numbers? I want to find the prime numbers between 20,000 and 10,000 and save that to a variable. primes(20000) gives me them all the way to zero and if i try to subtract primes(20000) and primes(10000) it won't let me because there not the same size. Any ideas? Thanks.
  1 commentaire
Jack Garvey
Jack Garvey le 31 Jan 2017
Modifié(e) : Walter Roberson le 31 Jan 2017
1.) make array of range: range = [10000:1:20000]
2.) create logical array of (range) displaying which numbers are prime: isprime(range)
3.) find total amount of prime numbers within that range: number_of_primes = sum(isprime(range))
4.) i got the answer of 1033 prime numbers between 10K and 20K

Connectez-vous pour commenter.

Réponse acceptée

Walter Roberson
Walter Roberson le 18 Sep 2011
setdiff(primes(20000),primes(10000))

Plus de réponses (1)

Andrei Bobrov
Andrei Bobrov le 18 Sep 2011
k = 1e4:2e4;
out = k(isprime(k));
variant
prms = primes(20000);
out = prms(prms>=10000);

Catégories

En savoir plus sur Matrix Indexing dans Help Center et File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by