R: Find All Primes Less Than n

Primes {DescTools} | R Documentation

## Find All Primes Less Than n

### Description

Find all prime numbers aka ‘primes’ less than n.

Uses an obvious sieve method and some care, working with logical and integers to be quite fast.

### Usage

    Primes(n)

### Arguments

`n` | a (typically positive integer) number.

### Details

As the function only uses `max(n)`, `n` can also be a vector of numbers.

### Value

numeric vector of all prime numbers <= n.

### Note

This function was previously published in the package sfsmisc as `primes` and has been integrated here without logical changes.

### Author(s)

Bill Venables (<= 2001); Martin Maechler gained another 40% speed, working with logicals and integers.

### See Also

`Factorize`, `GCD`, `LCM`, `IsPrime`

### Examples

    (p1 <- Primes(100))
    system.time(p1k <- Primes(1000)) # still lightning ..

    stopifnot(length(p1k) == 168)

[Package DescTools version 0.99.35 Index]