The loop is continuously running

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MA
MA on 17 Oct 2021
Commented: Scott MacKenzie on 17 Oct 2021
I am trying to compare the date values for two tables named T and S, if any matching of the dates is found we should copy the value of the variable 'solar' from S and add it to its corresponding date in T. I implemented that using the following for loop, but the loop keep continuously running for some reason. and we are not getting our desired result.
having that T is 37028x5 table and S is 25550x2 table.
how can we fix that or would there be a better way to do this rather than a for loop?
for jj=1:size(T)
for ii=1:size(S)
if (year(T.Date(jj))==year(S.date(ii)) & month(T.Date(jj))==month(S.date(ii)) & day(T.Date(jj))==day(S.date(ii)) )
T.solarT(jj)=S.solar(ii);
end
end
end
attached are parts of the tables S and T respectively,
thanks for giving it a look,

Accepted Answer

Scott MacKenzie
Scott MacKenzie on 17 Oct 2021
Your loop is fine, but is inefficient and takes a long time to execute. Instead of the loop, try this:
[Lia, Locb] = ismember(T.Date, S.date);
idx = Locb(Locb > 0);
T.solarT(Lia) = S.solar(idx);
  2 Comments
Scott MacKenzie
Scott MacKenzie on 17 Oct 2021
You're welcome. Glad to help.
Another approach to consider is converting the tables (which include datetime columns) to timetables and then using the synchronize function. Check the timetable documentation for examples.

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