Weekly retime grouping by ID on large dataset

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Gian23
Gian23 2021-9-24
评论： Gian23 2021-10-15
Hello everyone,
I'm going to calculate the weekly average of daily temperatures and pressure grouping by sensor using retime function. At the moment I'm trying to select each sensor with a loop and then apply the retime function, but I have to calculate nine million rows so I would like to avoid a loop to speed up the calculation
I give an example of input table:
MeasurementTime = datetime({'2015-11-11';'2015-11-12';'2015-11-23';'2015-11-23';'2015-12-04';'2015-12-08';'2015-12-10';'2015-12-11';'2015-12-12'});
Temp = [36.3;38.1;39.3;37.3;39.1;42.3;36.3;38.1;39.3];
Pressure = [29.9;29.1;29.3;30.4;30.3;29.9;30.1;30.6;29.6;];
Sensor = [121;121;143;143;121;143;121;143;143];
SensorState = ["T"; "T"; "T"; "T"; "W"; "T"; "T"; "W"; "W"];
TT = timetable(MeasurementTime,Sensor,SensorState,Temp,Pressure);
I give an example of output table:
MeasurementTime Temp Pressure Sensor SensorState
_______________ ____ ________ ______ ___________
08-Nov-2015 37.2 29.5 "121" "T"
15-Nov-2015 NaN NaN "121" "T"
22-Nov-2015 NaN NaN "121" "T"
22-Nov-2015 38.3 29.85 "143" "T"
29-Nov-2015 NaN NaN "121" "T"
29-Nov-2015 NaN NaN "143" "T"
29-Nov-2015 39.1 30.3 "121" "W"
06-Dec-2015 36.3 30.1 "121" "T"
06-Dec-2015 42.3 29.9 "143" "T"
06-Dec-2015 38.7 30.1 "143" "W"
Thanks in advance!

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采纳的回答

Cris LaPierre
Cris LaPierre 2021-9-24
编辑：Cris LaPierre 2021-9-24
Ran in:
Look into groupsummary. You can group by multiple variables.
% groupsummary
MeasurementTime = datetime({'2015-11-11';'2015-11-12';'2015-11-23';'2015-11-23';'2015-12-04';'2015-12-08';'2015-12-10';'2015-12-11';'2015-12-12'});
Temp = [36.3;38.1;39.3;37.3;39.1;42.3;36.3;38.1;39.3];
Pressure = [29.9;29.1;29.3;30.4;30.3;29.9;30.1;30.6;29.6;];
Sensor = [121;121;143;143;121;143;121;143;143];
SensorState = ["T"; "T"; "T"; "T"; "W"; "T"; "T"; "W"; "W"];
TT = timetable(MeasurementTime,Sensor,SensorState,Temp,Pressure);
wklyAvg = groupsummary(TT,["Sensor","MeasurementTime"],["none","week"],'mean',["Temp","Pressure"], 'IncludeMissingGroups',true,'IncludeEmptyGroups',true)
wklyAvg = 10×5 table
Sensor week_MeasurementTime GroupCount mean_Temp mean_Pressure ______ __________________________ __________ _________ _____________ 121 [08-Nov-2015, 15-Nov-2015) 2 37.2 29.5 121 [15-Nov-2015, 22-Nov-2015) 0 NaN NaN 121 [22-Nov-2015, 29-Nov-2015) 0 NaN NaN 121 [29-Nov-2015, 06-Dec-2015) 1 39.1 30.3 121 [06-Dec-2015, 13-Dec-2015) 1 36.3 30.1 143 [08-Nov-2015, 15-Nov-2015) 0 NaN NaN 143 [15-Nov-2015, 22-Nov-2015) 0 NaN NaN 143 [22-Nov-2015, 29-Nov-2015) 2 38.3 29.85 143 [29-Nov-2015, 06-Dec-2015) 0 NaN NaN 143 [06-Dec-2015, 13-Dec-2015) 3 39.9 30.033
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Gian23
Gian23 2021-10-15
Hi Cris, sorry for the delay in my answer. I tried your solution and run very fast. Thank you.

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