# How can I get the averages of each day of multiple years?

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Hendrik Van de Peer on 30 Nov 2020
Answered: Sindar on 2 Dec 2020
Hello,
I have a table with 3 collums: the first collum are dates over 4 years. The second and third collum are vallues of temperature and flowrate of a river for te corresponding date. The Temperature has some NaN's in the data. Nan's have to be ignored
I want to calculate the average temperature and flowrate on each day over this years. So I get a new table (365x3) with each date of the year with these avarage values.
Can someone help me to achive this please?
Thank you!
Mathieu NOE on 2 Dec 2020
ok ok just worrying about several sections of the final data that looked strange to me
• we can have a valid date and some data (or one data is NaN or both are NaN)
• we have sometimes both data with an invalid date ; NaT (not a time value)
so what do we do in this case ?
extract :
NaT 13.76 3
NaT 14.23 3
NaT 13.63 2.5
NaT 13.22 2.5
NaT 12.08 2.5
NaT 11.18 3
1/05/2006 10.42 3.5
2/05/2006 11.43 3
3/05/2006 13.66 3
4/05/2006 15.49 2.5
5/05/2006 15.77 2.5
6/05/2006 16.17 4
7/05/2006 15.44 2.5
8/05/2006 14.79 2.5
9/05/2006 14.69 3.5
10/05/2006 15.23 3.5
11/05/2006 15.43 3
12/05/2006 16.17 2.5
13/05/2006 16.14 3.5
14/05/2006 15.38 3.5
15/05/2006 14.91 3
16/05/2006 15.57 3
17/05/2006 15.97 3
18/05/2006 NaN 4
19/05/2006 15.5 3.5
20/05/2006 14.1 4.5
21/05/2006 13.84 4.5
22/05/2006 14.8 6
23/05/2006 14.5 4
24/05/2006 13.56 3.5
25/05/2006 13.1 5
26/05/2006 13.17 5.5
27/05/2006 14.01 7
28/05/2006 14.47 7.5
29/05/2006 13.95 5.5
30/05/2006 12.86 5.5
31/05/2006 12.08 4.5
NaT 11.76 4
NaT 11.96 4.5
NaT 13.27 3.5
NaT 14.1 3.5
NaT 14.68 3.5

Sindar on 2 Dec 2020
Check out groupsummary, specifically this example and this input argument
Also, this thread has some solutions related to leap years and NaN data