How do I generate the first n prime numbers?

最新推荐文章于 2022-05-11 14:32:24 发布

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最新推荐文章于 2022-05-11 14:32:24 发布

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本文介绍如何使用Ruby的Prime类高效生成并求和指定范围内的质数。通过利用Prime模块提供的方法，如Prime.each结合inject进行求和操作，可以简化质数生成及求和的过程。

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In Ruby 1.9 there is a Prime class you can use to generate prime numbers, or to test if a number is prime:

require 'prime'

Prime.take(10) #=> [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
Prime.take_while {|p| p < 10 } #=> [2, 3, 5, 7]
Prime.prime?(19) #=> true

            require 'prime'

Prime.first(10) # => [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
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I have a simple method that finds prime numbers, puts them in an array and then sums them up. What are some possible steps to speed it up?
            This should work.  It uses others' suggestions:
require 'prime'
def sum_prime(limit)
  Prime.each(limit).inject(0) {|sum, num| sum + num}
end
puts sum_prime(200000)