IsPrime {DescTools}

IsPrime Property

Description

Returns for a vector or matrix of positive integers a logical object of the same dimension(s) containing TRUE for the elements that are prime and FALSE otherwise.

Usage

IsPrime(x)

Arguments

x

vector or matrix of nonnegative integers

Details

Given a vector or a matrix of positive integers returns a vector of the same size of FALSE and TRUE. Use which(IsPrime(1:21)) to get the positions.

Value

logical vector

Author(s)

Hans W. Borchers <[e-mail]>

See Also

Factorize, Primes

Examples

x <- matrix(1:10, nrow=10, ncol=10, byrow=TRUE)
x * IsPrime(x)

# Find first prime number octett:
octett <- c(0, 2, 6, 8, 30, 32, 36, 38) - 19
while (TRUE) {
    octett <- octett + 210
    if (all(IsPrime(octett))) {
        cat(octett, "\n", sep="  ")
        break
    }
}