Creating a for loop to see if date exists

I have two array with date, first array have multiple dates in 5x3 cell such as each cell have year, month, and date in it:

firstarray=[2019 5 03;

2019 4 03;

2019 4 05;

2019 4 06;

2019 3 05]

Another array is 1x3 which has the date I am looking for.

[2019 4 05]

How can I create a for loop to find that date and find the position of where it is located?

Answer 1

[Rik]

If you insist or keeping it as a double, you can use ismember three times, but it makes more sense to make use of the datetime class.

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);

[Devarshi Patel]

Thank you so much! Work flawlessly!

[Steven Lord]

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]

Thank you! Your code worked as well!

Answer 2

[Peter Perkins]

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