Creating a for loop to see if date exists

first=[2019 5 03;
2019 4 03;
2019 4 05;
2019 4 06;
2019 3 05];
test=[2019 4 05];
first=datetime(first(:,1),first(:,2),first(:,3));
test=datetime(test(:,1),test(:,2),test(:,3));
pos=find(ismember(first,test));
date=first(pos);

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Steven Lord 2019-6-11

在 MATLAB Online 中打开

If you need to keep first and test as double arrays, don't call ismember three times. Call it once with the 'rows' option.

first=[2019 5 03;
2019 4 03;
2019 4 05;
2019 4 06;
2019 3 05];
test=[2019 4 05; 2019 4 04];
[isPresent, wherePresent] = ismember(test, first, 'rows')
matched = [test(isPresent, :), first(wherePresent(isPresent), :)]
unmatched = test(~isPresent, :)

Devarshi Patel 2019-6-12

Thank you! Your code worked as well!

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Answer 2

Peter Perkins 2019-6-12

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/466567-creating-a-for-loop-to-see-if-date-exists#answer_378885

在 MATLAB Online 中打开

Also, it may be that you need to "find that date and find the position of where it is located" because you'll then use that location to index into somethign else. If that's truem sacve yourself a lot of hassle, and create a timetable. For example:

>> t = timetable([1;2;3;4;5],'RowTimes',datetime(2019,6,[1 2 3 5 9]))
t =
  5×1 timetable
       Time        Var1
    ___________    ____
    01-Jun-2019     1  
    02-Jun-2019     2  
    03-Jun-2019     3  
    05-Jun-2019     4  
    09-Jun-2019     5  
>> t.Var1('5-Jun-2019')
ans =
     4