ruby - ruby 的日期范围内特定日期出现了多少次？

Question

我有两个日期，即

start date = "2013-06-01" 
end date = "2013-12-01"

我正在尝试实现在此日期范围内出现多少次星期一和星期二？

specific_days = 2 #monday and tuesday
total days = end_date - start_date 
total_weeks = total_days/7
total_specific_days = total_weeks * specific_days

但这并不能保证周一和周二发生

Answer 1

使用wday method返回星期几的 Date 类(0-6，星期日为零)，因此星期一为 1，星期二为 2。

require 'date'
dates = [*Date.new(2014,1,1)..Date.new(2014,10,1)]
p dates.count{|d| (d.wday == 1) || (d.wday == 2) }

结果:

#=> 78

已更新

比较数组和范围集:

require 'date'
require 'benchmark'

d1 = [*Date.new(2013,2,11)..Date.new(2013,12,25)]
d2 = Date.new(2013,2,11)..Date.new(2013,12,25)

n = 10000
Benchmark.bm do |x|
  x.report('array') { n.times do d1.count{|d| (d.wday == 1) || (d.wday == 2) }; end }
  x.report('range') { n.times do d2.count{|d| (d.wday == 1) || (d.wday == 2) }; end }
end

结果:

         user     system      total        real
array  0.405000   0.000000   0.405000 (  0.419041)
range  1.498000   0.000000   1.498000 (  1.505150)