Adding data based on datetime index

Asked Feb 21 '19 at 12:22

Active Feb 21 '19 at 13:12

Viewed 90 times

I have the below code

dateseries=pd.date_range('1996-10-31','2019-01-05',freq='B')
df1['Date']=pd.DataFrame(dateseries,columns=['Date'])

I want to add a column for sum for each date in this dataframe (df) from another dataframe (say df2, that has multiple values for same date) based on date filters

df1
Date
1996-10-31
1996-11-01
1996-11-02

df2
Date       Val   
1996-10-31   5
1996-10-31   6
1996-10-31   4
1996-11-01   7
1996-11-01   9

I want the final output in df1 as below

df1
Date        Val
1996-10-31   15
1996-11-01   16

edited Feb 21 '19 at 13:12

trotta

1,232
1
16
23

asked Feb 21 '19 at 12:22

Prakash Chidamparam

Hello Prakash, what have you tried so far? – ferrix Feb 21 '19 at 12:37
I tried using .loc and specify dates, it was working if datetime index is not there. since I have a datetime index, I'm not able to specify location based on .loc – Prakash Chidamparam Feb 21 '19 at 12:54
I'm a new user in python, just learning for the past two days – Prakash Chidamparam Feb 21 '19 at 12:55
This is not really Python but Pandas. And what you want is probably the `groupby` method of Pandas dataframes. What about `df2.groupby('Date').sum()`? – Serge Ballesta Feb 21 '19 at 13:25
Thanks Serge. That's helpful – Prakash Chidamparam Feb 21 '19 at 13:33

Adding data based on datetime index

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