MATLAB Answers

Convert Columns Arrays to numeric

7 views (last 30 days)
Hi,
I have a timetable with various data columns - I have imported these from an excel file. I need to make an addition to the all rows of colums and to add a column with the result. I think that my arrays are currently not numeric type and therefor I can not add them. Is there a way that I can convert data of columns 1-7 to numeric and make a summation? Or how can I know the data type of the columns?
1.PNG

  1 Comment

Andrei Bobrov
Andrei Bobrov on 15 Jan 2020
Please attach here your variable 'combine' as mat-file
>> save('yourdata.mat','combine') % run in yur Command Window
And attach here file yourdata.mat .

Sign in to comment.

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 15 Jan 2020
Edited: Andrei Bobrov on 15 Jan 2020
...how can I know the data type of the columns?
varfun(@class,combine)
solution:
load('data.mat')
combine = [combine,rowfun(@funsum,combine,'OutputVariableName','SUM_ALL_kW')];
function out = funsum(varargin)
out = sum([varargin{:}],2);
end
or
combine.SUM_ALL_kW = sum(combine{:,:},2) ;

  2 Comments

Andrei Bobrov
Andrei Bobrov on 15 Jan 2020
Comment by Stefan Azzopardi:
Andrei, Thanks for your help and it worked perfectly. This resulted in a new column with the sum of the other columns. Thank you once again for your help :) :)
Andrei Bobrov
Andrei Bobrov on 15 Jan 2020
Stefan! If my answer solved your problem, then please accept it.

Sign in to comment.

More Answers (2)

WalterWhite
WalterWhite on 15 Jan 2020
t = datetime('now')
nn = datenum(t)+10;
f= datetime(nn,'ConvertFrom','datenum')
>> reading
t =
datetime
15-Jan-2020 09:52:43
f =
datetime
25-Jan-2020 09:52:43
did you mean something like this?

  1 Comment

Stefan Azzopardi
Stefan Azzopardi on 15 Jan 2020
thank you for your help Walter, but it is not exactly what I meant. Anyway, I got all the help that I requested from Andrei :) :)

Sign in to comment.


Steven Lord
Steven Lord on 15 Jan 2020
Using the example from the timetable help text:
MeasurementTime = datetime({'2015-12-18 08:03:05';'2015-12-18 10:03:17';'2015-12-18 12:03:13'});
Temp = [37.3;39.1;42.3];
Pressure = [30.1;30.03;29.9];
WindSpeed = [13.4;6.5;7.3];
WindDirection = categorical({'NW';'N';'NW'});
TT = timetable(MeasurementTime,Temp,Pressure,WindSpeed,WindDirection)
Let's say that I wanted (for whatever reason) to add the temperature, pressure, and wind speed. I can extract that data from TT into a numeric array in two different ways:
A1 = TT{:, ["Temp", "Pressure", "WindSpeed"]} % Using variable names
A2 = TT{:, 1:3} % Using variable numbers
Now sum and put back into TT.
TT.combinedData = sum(A1, 2)
If all your data could be concatenated into an array with a uniform type, you could extract the data even easier. But this technique won't work for TT, as you can't combine a numeric variable like TT.Temp and a categorical variable like TT.WindDirection into one array.
TT.Variables

  0 Comments

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!