Time.now vs Time.new in Ruby

Question

Time.now和Time.new（没有参数）之间有什么区别吗？可能是内存管理或一些小细节方面的差异？

Answer 1

没有区别。

Time.now是：：new的别名。返回初始化为的Time对象当前系统时间。

http://www.ruby-doc.org/core-2.1.4/Time.html#method-c-now

Answer 2

now是new的别名。他们之间没有区别。Jeff price首先要回答（他的答案也是正确的，如果你喜欢的话，请投票给他的答案），因为我正在编写和运行这个基准：

Ruby 2.1.2（MRI）：

Rehearsal ----------------------------------------------------------------------------
Time.new                                   0.670000   0.000000   0.670000 (  0.679709)
Time.now                                   0.880000   0.010000   0.890000 (  0.881899)
------------------------------------------------------------------- total: 1.560000sec
                                               user     system      total        real
Time.new                                   0.720000   0.000000   0.720000 (  0.719453)
Time.now                                   0.740000   0.010000   0.750000 (  0.742711)
Rehearsal ----------------------------------------------------------------------------
Time.new                                   0.810000   0.000000   0.810000 (  0.811874)
Time.now                                   0.830000   0.000000   0.830000 (  0.831346)
------------------------------------------------------------------- total: 1.640000sec
                                               user     system      total        real
Time.new                                   0.790000   0.010000   0.800000 (  0.800082)
Time.now                                   0.740000   0.000000   0.740000 (  0.749995)
Rehearsal ----------------------------------------------------------------------------
Time.new                                   0.680000   0.010000   0.690000 (  0.690337)
Time.now                                   0.850000   0.000000   0.850000 (  0.856800)
------------------------------------------------------------------- total: 1.540000sec
                                               user     system      total        real
Time.new                                   0.790000   0.010000   0.800000 (  0.792666)
Time.now                                   0.770000   0.000000   0.770000 (  0.777414)
Rehearsal ----------------------------------------------------------------------------
Time.new                                   0.590000   0.010000   0.600000 (  0.594650)
Time.now                                   0.710000   0.010000   0.720000 (  0.717067)
------------------------------------------------------------------- total: 1.320000sec
                                               user     system      total        real
Time.new                                   0.870000   0.000000   0.870000 (  0.872646)
Time.now                                   0.680000   0.010000   0.690000 (  0.687092)
Rehearsal ----------------------------------------------------------------------------
Time.new                                   0.780000   0.010000   0.790000 (  0.786419)
Time.now                                   0.780000   0.000000   0.780000 (  0.789049)
------------------------------------------------------------------- total: 1.570000sec
                                               user     system      total        real
Time.new                                   0.760000   0.010000   0.770000 (  0.768194)
Time.now                                   0.790000   0.010000   0.800000 (  0.790981)

自己运行基准测试：

n = 1000000
5.times do 
  Benchmark.bmbm(40) do |x|
    x.report("Time.new"){ n.times { Time.new } }
    x.report("Time.now"){ n.times { Time.now } }
  end
end

Answer 3

使用Ruby 2.4.1和Rails 5.0.3当在测试中使用travel_to时，Time.new不会受到它的影响，但Time.now确实会因此而更改