如何测试对象是否是一个熊猫日期时间索引?

If I use type on a DataFrame which I know has a datetime index, I get:

如果我在一个DataFrame上使用类型，我知道它有一个datetime索引，我得到:

In [17]: type(df.index)
Out[17]: pandas.tseries.index.DatetimeIndex

but when I test it, I get:

但当我测试它时，我得到:

In [18]: type(df.index) == 'pandas.tseries.index.DatetimeIndex'
Out[18]: False

I know I assumed the type of type is a string, but I really don't know what else to try, and searching has resulted in nothing.

我知道我假设类型是字符串，但我真的不知道还需要尝试什么，搜索没有结果。

3 个解决方案

#1

You can use isinstance of the DatetimeIndex class:

您可以使用DatetimeIndex类的isinstance:

In [11]: dates = pd.date_range('20130101', periods=6)

In [12]: dates
Out[12]: 
<class 'pandas.tseries.index.DatetimeIndex'>
[2013-01-01 00:00:00, ..., 2013-01-06 00:00:00]
Length: 6, Freq: D, Timezone: None

In [13]: isinstance(dates, pd.DatetimeIndex)
Out[13]: True

#2

What did you import Pandas as?

你们进口的熊猫是什么?

If you are following the guide in the documentation and did something like:

如果你遵循文档中的指南并做了一些类似的事情:

import pandas as pd
dates = pd.date_range('20130101', periods=6)

type(dates[0]) 
pandas.tslib.TimestampTimestamp('2013-01-01 00:00:00', tz=None)

type(dates[0]) == pandas.tslib.Timestamp
False  
# this throws NameError since you didn't import as pandas

type(dates[0]) == pd.tslib.Timestamp
True  
# this works because we imported Pandas as pd

Out of habit I neglected to mention as @M4rtini highlighted that you should not be using a string to compare equivalency.

出于习惯，我忘了提到@M4rtini强调了不应该使用字符串来比较相等性。

#3

In [102]: type("asd") == str
Out[102]: True

In [103]: type("asd") == "str"
Out[103]: False

Compare against the object, not a string.

比较对象，而不是字符串。

#1