我有一个如下所示的 Pandas DataFrame。
df
A B
date_time
2014-07-01 06:03:59.614000 62.1250 NaN
2014-07-01 06:03:59.692000 62.2500 NaN
2014-07-01 06:13:34.524000 62.2500 241.0625
2014-07-01 06:13:34.602000 62.2500 241.5000
2014-07-01 06:15:05.399000 62.2500 241.3750
2014-07-01 06:15:05.399000 62.2500 241.2500
2014-07-01 06:15:42.004000 62.2375 241.2500
2014-07-01 06:15:42.082000 62.2375 241.3750
2014-07-01 06:15:42.082000 62.2375 240.2500
我想将其频率更改为定期1 minute间隔。但得到以下错误：
new = df.asfreq('1Min')
>>error: cannot reindex from a duplicate axis
现在，我明白为什么会这样了。由于我的时间粒度很高（以毫秒为单位）但不规则，我每分钟甚至每秒都会获得多个读数。因此，我尝试将这些毫秒读数与分钟相结合，并消除重复项，如下所示。
# try to convert the index to minutes and drop duplicates
df['index'] = df.index
df['minute_index']= df['index'].apply( lambda x: x.strftime('%Y-%m-%d %H:%M'))
df.drop_duplicates(cols = 'minute_index', inplace = True, take_last = True)
df_by_minute = df.set_index('minute_index')
df_by_minute
A B index
minute_index
2014-07-01 06:03 62.2500 NaN 2014-07-01 06:03:59.692000
2014-07-01 06:13 62.2500 241.50 2014-07-01 06:13:34.602000
2014-07-01 06:15 62.2375 240.25 2014-07-01 06:15:42.082000
# now change the frequency to 1 minute but I just get NaNs (!)
df_by_minute.asfreq('1Min')
A B index
2014-07-01 06:03:00 NaN NaN NaT
2014-07-01 06:04:00 NaN NaN NaT
2014-07-01 06:05:00 NaN NaN NaT
2014-07-01 06:06:00 NaN NaN NaT
2014-07-01 06:07:00 NaN NaN NaT
2014-07-01 06:08:00 NaN NaN NaT
2014-07-01 06:09:00 NaN NaN NaT
2014-07-01 06:10:00 NaN NaN NaT
2014-07-01 06:11:00 NaN NaN NaT
2014-07-01 06:12:00 NaN NaN NaT
2014-07-01 06:13:00 NaN NaN NaT
2014-07-01 06:14:00 NaN NaN NaT
2014-07-01 06:15:00 NaN NaN NaT
如您所见，它不起作用..有人可以帮忙吗？我想要实现的是获得一个返回的函数，A or B as of DateTime并且 DateTime 将以 1Min 为增量。