R: Find prime numbers in an array

primes.md

R function to find prime numbers in an array

The functions:

check.integer <- function(x) { x == round(x) }
 
is.prime <- function(y) { !check.integer(y/2) &
                          !check.integer(y/3) &
                          !check.integer(y/5) &
                          !check.integer(y/7) }
 
find.primes <- function(z) { z <- z[z > 1]
                             primes <- c(2,3,5,7)
                             primes <- primes[primes >= min(z)]
                             for(i in z) { if(is.prime(i)==TRUE) primes <- c(primes,i) }
                             print(primes) }

Example:

find.primes(7:37)

Output:

[1]  7 11 13 17 19 23 29 31 37