python - 使用 pandas.Series.asof : can't compare datetime. 日期时间到 str 时出错

Question

如何使用Series.asof函数？我传入了一个 datetime 对象 datetime.strptime('20150101', '%Y%m%d')，但为什么会报错

  File "/Users/x/anaconda/envs/test/lib/python2.7/site-packages/pandas/core/series.py", line 2460, in asof
    if where < start:
TypeError: can't compare datetime.datetime to str

使用的代码是:

import pandas as pd
from datetime import datetime

names = ['mary', 'john', 'tom']
dates = [datetime.strptime('20130101', '%Y%m%d'), 
         datetime.strptime('20140101', '%Y%m%d'), 
         datetime.strptime('20150101', '%Y%m%d')]
mySeries = pd.Series(dates, names)

print mySeries.asof(datetime.strptime('20140101', '%Y%m%d'))

我怎么用错了？

Answer 1

您的数据和索引在mySeries 中是相反的。该索引需要是一个 TimeSeries。

mySeries = pd.Series(data=names, index=dates)
>>> print mySeries.asof(datetime.strptime('20140101', '%Y%m%d'))
john