创建每月 pandas DatetimeIndex

Question

我有一个包含 12 个值的数据框，我想将其转换为 DatetimeIndex 类型

months = df['date'] #e.g. '2016-04-01'
idx = pd.date_range(months[0], months[11], freq='M')

但是得到的DatetimeIndex长度只有11，应该是12 不确定是不是因为频率的原因，它会将日期移到月底？

Answer 1

我用 periods 生成：

print df
         date
0  2016-01-01
1  2016-02-01
2  2016-03-01
3  2016-04-02

print pd.date_range(df['date'].iloc[0], periods=12, freq='M')
DatetimeIndex(['2016-01-31', '2016-02-29', '2016-03-31', '2016-04-30',
               '2016-05-31', '2016-06-30', '2016-07-31', '2016-08-31',
               '2016-09-30', '2016-10-31', '2016-11-30', '2016-12-31'],
              dtype='datetime64[ns]', freq='M')

为什么缺少最后一个值 - check in the end:

months = df['date'] 
print pd.date_range(months.iloc[0], months.iloc[3], freq='M')
DatetimeIndex(['2016-01-31', '2016-02-29', '2016-03-31'], dtype='datetime64[ns]', freq='M')

The start and end dates are strictly inclusive. So it will not generate any dates outside of those dates if specified.

创建每月 pandas DatetimeIndex

Create monthly pandas DatetimeIndex

python

pandas

datetimeindex