我有以下pandas dataframe索引到time_stamp:
df = DataFrame(index = pd.date_range('4/1/2017', freq='3D', periods=10))
df['weekday'] = df.index.weekday_name
数据看起来像这样:
weekday
2017-04-01 Saturday
2017-04-04 Tuesday
2017-04-07 Friday
2017-04-10 Monday
2017-04-13 Thursday
2017-04-16 Sunday
2017-04-19 Wednesday
2017-04-22 Saturday
2017-04-25 Tuesday
2017-04-28 Friday
我想创建一个新专栏的"周",该专栏将使一周的年度序言,但有一个工作日。
我知道我可以做到这一点:
df['week_sun'] = df.index.week
除了我希望本周的第一天除了星期日之外。对于这个问题,可以说我需要它是星期三,以便由此产生的数据框架就是这样:
weekday week_sun week_wed
2017-04-01 Saturday 13 13
2017-04-04 Tuesday 14 13
2017-04-07 Friday 14 14
2017-04-10 Monday 15 14
2017-04-13 Thursday 15 15
2017-04-16 Sunday 15 15
2017-04-19 Wednesday 16 16
2017-04-22 Saturday 16 16
2017-04-25 Tuesday 17 16
2017-04-28 Friday 17 17
我无法实现这一目标。谢谢!
鉴于您的要求,您只需要将1减为一周的编号,以防一周中的一天"在"参考日"之前(您的示例中的星期三)。
In [162]: df
Out[162]:
weekday week_sun
2017-04-01 Saturday 13
2017-04-04 Tuesday 14
2017-04-07 Friday 14
2017-04-10 Monday 15
2017-04-13 Thursday 15
2017-04-16 Sunday 15
2017-04-19 Wednesday 16
2017-04-22 Saturday 16
2017-04-25 Tuesday 17
2017-04-28 Friday 17
In [163]: df['week_wed'] = df['week_sun']
现在让我们在需要的地方转移价值,这意味着当工作日是星期三之前的时候,因此df.index.dayofweek < 2
。
In [164]: df.loc[df.index.dayofweek < 2, 'week_wed'] = (df[df.index.dayofweek < 2]['week_sun'] - 2) % 52 + 1
In [165]: df
Out[165]:
weekday week_sun week_wed
2017-04-01 Saturday 13 13
2017-04-04 Tuesday 14 13
2017-04-07 Friday 14 14
2017-04-10 Monday 15 14
2017-04-13 Thursday 15 15
2017-04-16 Sunday 15 15
2017-04-19 Wednesday 16 16
2017-04-22 Saturday 16 16
2017-04-25 Tuesday 17 16
2017-04-28 Friday 17 17
我并没有完全减去1,而是使用Modulo操作((X-2) %52 +1)
),因此我可以将第1周转换为上一年的第52周,如果需要:
weekday week_sun week_wed
2017-12-27 Wednesday 52 52
2017-12-30 Saturday 52 52
2018-01-02 Tuesday 1 52
2018-01-05 Friday 1 1