Campus Livre
isprime
Tests which elements are prime numbers.
Category: Mathematics > Elementary Math
Syntax
TF = isprime(X)Returns a logical array that is true where the element of X is prime.
Description
A prime is an integer greater than 1 whose only positive divisors are 1 and itself. So 0 and 1 are not prime, and 2 is the only even prime.
Combine with find to list primes in a range, or with sum to count them: sum(isprime(1:100)) is 25.
Input arguments
X- Array of nonnegative integer values (any numeric class).
Output arguments
TF- Logical array of the same size as
X.
Example
Primes up to 10 and a Mersenne prime
isprime(1:10)
isprime(2^31 - 1)
sum(isprime(1:100))Output
ans = 1×10 logical array
0 1 1 0 1 0 1 0 0 0
ans = logical
1
ans = 25