Setting freq of pandas DatetimeIndex after DataFrame creation

Question

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')

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]]

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

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.

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

Answer 1

Try:

ABB = ABB.asfreq('d') 

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

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

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

Thanks!

Answer 2

ABB is pandas DataFrame, whose index type is DatetimeIndex.

DatetimeIndex has freq attribute which can be set as below

ABB.index.freq = 'd'

Check out the change

ABB.index