Question

我有两个日期，即

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

我想要达到星期一和星期二在这个日期范围内发生多少次？

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

但这并不能确保星期一和星期二的出现

Answer 1

使用Date类的wday method返回星期几（0-6，星期日为零），因此Mon为1，Tue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

<强>更新

比较array和range套：

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)

Answer 2

使用Date#monday?，Date#tuesday?和Enumerable#count更加冗长：

require 'date'
start_date = Date.parse("2013-06-01")
end_date = Date.parse("2013-12-01")

(start_date..end_date).count { |d| d.monday? || d.tuesday? }
#=> 78

Answer 3

此问题与How do I get all Sundays between two dates in Ruby?非常相似。

获取此日期之间的所有日期，并选择工作日编号为1或2的日期。星期日是第一个工作日（= 0）。

require 'date'

start_date = DateTime.parse('2013-06-01')
end_date = DateTime.parse('2013-12-01')

result = (start_date..end_date).to_a.select { |d| [1,2].include?(d.wday) }

result.count

结果为52次。

Answer 4

=> (Date.parse(start_date)..Date.parse(end_date)).count{|d| d.wday == 1 || d.wday == 2 }
# 52

在红宝石的日期范围内特定天数发生了多少次？

4 个答案: