irb(main):022:0* 1.next
=> 2
irb(main):023:0> "a".next
=> "b"
irb(main):024:0> "1".next
=> "2"
irb(main):025:0>

require 'benchmark'

n=(1..1000000).to_a
def num_next(first,last)
    while first != last
            first=first.next
    end
    
end


def num_join(first,last)
        while first != last
              first+=1
        end
end

Benchmark.bm do |bm|
    bm.report("each") do 
        n.each do |d|
            d
        end
    end

    bm.report("next") do 
        num_next(1,1000000)
    end

    bm.report("  + ") do 
        num_join(1,1000000)
    end
end

输出：
      user     system      total        real
each  0.219000   0.000000   0.219000 (  0.218000)
next  0.266000   0.000000   0.266000 (  0.266000)
  +   0.312000   0.000000   0.312000 (  0.313000)