Ruby - 获取两个日期之间的月份范围

Question

我生成了一个名为的表DimensionDate,其中包含2011,12,31和2032,1,1之间的所有日期.

现在,我想知道这两个日期之间每个日期的绝对范围.

例如 :

2012-01-01是1个月

2012-02-01是2个月

2013-01-01是13个月

2013-02-01是14个月

2014-01-01是25个月

2014-02-01是26个月

等等...

我怎么能这样做？任何的想法 ？谢谢你的帮助

Answer 1

像这样的东西？

require 'date'

def months_between_dates(date_1, date_2)
  diff_in_years  = (date_1.year-date_2.year)*12
  diff_in_months = date_1.month-date_2.month
  return (diff_in_years + diff_in_months).abs
end

start_date  = Date.new(2011,12,31)
test_date   = Date.new(2013,01,01)
test_date_2 = Date.new(2014,02,01)

p months_between_dates(start_date, test_date)   # => 13
p months_between_dates(start_date, test_date_2) # => 26

编辑:

如果您知道您将始终与特定日期进行比较,则此处的奖励是具有默认值的版本.逻辑是相同的,只是简短而不是可读:

# Call by passing one or two dates:
def delta_months(x, y=Date.new(2011,12,31))
  ((x.year-y.year)*12+(x.month-y.month)).abs 
end

p delta_months(test_date)  # => 13

EDIT2:

正如dax指出我的函数不提供任何形式的验证,这里是你如何实现:

MIN_DATE, MAX_DATE = Date.new(2011,12,31), Date.new(2032,1,1)
date_range = MIN_DATE..MAX_DATE
test_date  = Date.new(2064,1,1)

raise "Date out of range, must be between #{MIN_DATE} and #{MAX_DATE}." unless date_range.cover? test_date # => Date out of range, must be between 2011-12-31 and 2032-01-01. (RuntimeError)
delta_months(test_date)  # Never called unless good date is provided.