Question

如何快速制作包含日期键的哈希

喜欢

start_date = Date.new(2017, 1, 9)
end_date  = Date.new(2017, 1, 12)

如何获得

result = 
{
  "2017-01-09": "",
  "2017-01-10": "",
  "2017-01-11": "",
  "2017-01-12": "",
}

Answer 1

DECLARE
   Date_Parameter date;
   Max_Month date;
BEGIN
  Date_Parameter := DATE '2017-04-01';
  select max(month) into Max_month from BALANCE_YEAR2;
select 
(
  IF Date_Parameter <= Max_month THEN
    OPEN :to_grid FOR
      select sum(FLARE_MTD_KNM3) FLARE_MTD_KNM3
      from BALANCE_YEAR2
      where month between trunc(Date_Parameter, 'YEAR')
        and LAST_DAY(date_parameter);
  ELSE
    OPEN :to_grid FOR
      select NET_VOL_MTD_KNM3
      from STREAM_D
      where code = 'FLARE' 
      and production_day = LAST_DAY(Date_Parameter)
  END IF
),
(
   select sum(max(case when code = 'U900' then volume else  null end )) CORR
     from BALANCE_YEAR1
         where production_day between trunc(Date_Parameter, 'YEAR') and Max_month 
              group by production_day
) from dual;
END;
/

或

(start_date..end_date).map(&:to_s).product([""]).to_h

@Stefan在评论中正确注意到

NB ，在上面的两个片段中，所有哈希值都引用相同的(start_date..end_date).map(&:to_s).zip([""].cycle).to_h实例。如果它不是一个选项，那么你手头有另一个（我最喜欢的）解决方案：

String

后一种解决方案有一个额外的好处：

Hash.new { |h, k| h[k.to_s] = ""}.tap do |h|
  h.values_at(*(start_date..end_date))
end

现在让我们来处理新的日期：

hash = Hash.new { |h, k| h[k.to_s] = ""}.tap do |h|
  h.values_at(*(start_date..end_date))
end
#⇒ {"2017-01-09"=>"", ... "2017-01-12"=>""}

Answer 2

(start_date..end_date).each_with_object({}) { |date, hash| hash[date.to_s] = '' }
#=> {"2017-01-09"=>"", "2017-01-10"=>"", "2017-01-11"=>"", "2017-01-12"=>""}

Answer 3

您只需使用

即可

 df_ID = pd.DataFrame({'Name': ['CTA15', 'CTA16'],
                        'AA_ID': [22, 22'],
                         'BB_ID':[4, 5],
                           'CC_ID' : [2, 2]})

Ruby生成日期密钥哈希

3 个答案: