primes function

6 ビュー (過去 30 日間)
Sean Smith
Sean Smith 2011 年 9 月 18 日
編集済み: Walter Roberson 2017 年 1 月 31 日
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 件のコメント
Jack Garvey
Jack Garvey 2017 年 1 月 31 日
編集済み: Walter Roberson 2017 年 1 月 31 日
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

サインインしてコメントする。

採用された回答

Walter Roberson
Walter Roberson 2011 年 9 月 18 日
setdiff(primes(20000),primes(10000))

その他の回答 (1 件)

Andrei Bobrov
Andrei Bobrov 2011 年 9 月 18 日
k = 1e4:2e4;
out = k(isprime(k));
variant
prms = primes(20000);
out = prms(prms>=10000);

カテゴリ

Help Center および File ExchangeLoops and Conditional Statements についてさらに検索

Community Treasure Hunt

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

Start Hunting!

Translated by