Question

Time.now和Time.new之间是否有区别（没有参数）？可能是内存管理方面的差异还是一些小细节？

Answer 1

没有区别。

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

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

Answer 2

now是new的别名。它们之间没有区别。杰夫的价格得到回答（他的回答也是正确的，如果你愿意的话请投票给他答案）首先，因为我正在编写并运行这个基准：

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：

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 在测试中使用travel_to时，Time.new不会受到它的影响，但是Time.now确实会因此而改变

Time.now与Time.new在Ruby中

3 个答案: