python - 如何从 Pandas DateTime Index 中删除时间值？

Question

从 cvs 文件中读取。

df = pd.read_csv(filename, sep=";", names=['DateTime','Open','High','Low','Close','Vol'],
                 parse_dates = [0], index_col = 'DateTime')

输出数据:

                            Open     High      Low    Close
DateTime                                                     
2016-01-03 00:00:00+00:00  1.08701  1.08723  1.08451  1.08515
2016-01-04 00:00:00+00:00  1.08701  1.09464  1.07811  1.08239
2016-01-05 00:00:00+00:00  1.08238  1.08388  1.07106  1.07502
2016-01-06 00:00:00+00:00  1.07504  1.07994  1.07185  1.07766
2016-01-07 00:00:00+00:00  1.07767  1.09401  1.07710  1.09256
2016-01-08 00:00:00+00:00  1.09255  1.09300  1.08030  1.09218

如何从上述日期时间索引中删除时间值？

另一个问题，如何将开盘价/最高价/最低价/收盘价中的值截断为小数点后 6 位？

Answer 1

要截断日期时间，首先将对象放入 DateTime 对象中，因为它会对此进行适当的处​​理。例如，在打印时，它只会打印日期值，因为时间始终为 0。

>>> c = pd.read_csv("a.csv", sep=",", names=['DateTime','Open','High','Low','Close','Vol'])
>>> c
                    DateTime     Open     High      Low    Close  Vol
0  2016-01-03 00:00:00+00:00  1.08701  1.08723  1.08451  1.08515  NaN
1  2016-01-04 00:00:00+00:00  1.08701  1.09464  1.07811  1.08239  NaN
2  2016-01-05 00:00:00+00:00  1.08238  1.08388  1.07106  1.07502  NaN
3  2016-01-06 00:00:00+00:00  1.07504  1.07994  1.07185  1.07766  NaN
4  2016-01-07 00:00:00+00:00  1.07767  1.09401  1.07710  1.09256  NaN
5  2016-01-08 00:00:00+00:00  1.09255  1.09300  1.08030  1.09218  NaN
>>> c.DateTime = pd.to_datetime(c.DateTime)
>>> c
    DateTime     Open     High      Low    Close  Vol
0 2016-01-03  1.08701  1.08723  1.08451  1.08515  NaN
1 2016-01-04  1.08701  1.09464  1.07811  1.08239  NaN
2 2016-01-05  1.08238  1.08388  1.07106  1.07502  NaN
3 2016-01-06  1.07504  1.07994  1.07185  1.07766  NaN
4 2016-01-07  1.07767  1.09401  1.07710  1.09256  NaN
5 2016-01-08  1.09255  1.09300  1.08030  1.09218  NaN

这通常会节省时间(如果存在的话)，只是这里不显示它，因为时间值为 0。要仅获取日期，请执行以下操作:

>>> c.DateTime = c.DateTime.dt.date
>>> c.DateTime[0]
datetime.date(2016, 1, 3)