在创建DataFrame之后设置 pandas DatetimeIndex的频率 [英] Setting freq of pandas DatetimeIndex after DataFrame creation

问题描述

我正在使用pandas datareader来获取库存数据.

Im using pandas datareader to get stock data.

import pandas as pd
import pandas_datareader.data as web
ABB = web.DataReader(name='ABB.ST', 
                     data_source='yahoo',
                     start='2000-1-1')

但是默认情况下，未在结果数据帧上设置freq. 我需要freq才能使用这样的索引进行导航:

However by default freq is not set on the resulting dataframe. I need freq to be able to navigate using the index like this:

for index, row in ABB.iterrows():
    ABB.loc[[index + 1]]

如果未在DatetimeIndex上设置频率，则无法使用+1等进行导航.

If freq is not set on DatetimeIndex im not able to use +1 etc to navigate.

我发现有两个功能astype和resample.由于我已经知道频率resample看起来有些过激，所以我只想将频率设置为每天.

What I have found are two functions astype and resample. Since I already know to freq resample looks like overkill, I just want to set freq to daily.

现在我的问题是如何在ABB上使用astype将频率设置为每日?

Now my question is how can i use astype on ABB to set freq to daily?

推荐答案

尝试:

ABB = ABB.asfreq('d')

这应将频率更改为每天使用NaN连续几天无数据.

This should change the frequency to daily with NaN for days without data.

此外，您还应该按如下方式重写for-loop:

Also, you should rewrite your for-loop as follows:

for index, row in ABB.iterrows():
    print(ABB.loc[[index + pd.Timedelta(days = 1)]])

谢谢！

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