MATLAB: Can I merge two matrices of different length with respect to a date column contained in both

matrix manipulationmergetime series

I have two matrices each containing date numbers in the first and observations in the second column. I would like to merge them so that my new matrix only contains the dates present in both matrices and the matching observations – it should be a three column matrix [dates obsMatrix1 obsMatrix2]

Best Answer

Take a look at INTERSECT. Something along these lines could work:

[~,i,j] = intersect(A(:,1),B(:,1))
C = [A(i,:) B(j,2)]

Related Solutions

MATLAB: How to have datetime for specific range

Try this:

dt1 = datetime([1982 01 01]);
dt2 = datetime([2015 12 31]);
dt_vec = dt1 : calmonths(1) : dt2;
FirstFive = dt_vec(1:5)                         % Display Results (Delete Later)

producing:

FirstFive = 
  1×5 datetime array
   01-Jan-1982   01-Feb-1982   01-Mar-1982   01-Apr-1982   01-May-1982

MATLAB: How to choose some rows of a table by order

It sounds like a grouped varfun is what you're looking for:

>> item = randi([1 3],10,1);
>> date = datetime(2016,12,randi([1 3],10,1));
>> cost = round(10*rand(10,1),2);
>> t = table(item,date,cost)
t =
    item       date        cost
    ____    ___________    ____
    3       03-Dec-2016    3.52
    1       01-Dec-2016    8.31
    2       03-Dec-2016    5.85
    3       01-Dec-2016     5.5
    3       03-Dec-2016    9.17
    3       02-Dec-2016    2.86
    2       01-Dec-2016    7.57
    1       01-Dec-2016    7.54
    1       02-Dec-2016     3.8
    1       02-Dec-2016    5.68
>> varfun(@topThree,t,'GroupingVariable','date','InputVariable','cost')
ans =
       date        GroupCount    topThree_cost
    ___________    __________    _____________
    01-Dec-2016    4             8.31         
    01-Dec-2016    4              5.5         
    01-Dec-2016    4             7.57         
    02-Dec-2016    3             2.86         
    02-Dec-2016    3              3.8         
    02-Dec-2016    3             5.68         
    03-Dec-2016    3             3.52         
    03-Dec-2016    3             5.85         
    03-Dec-2016    3             9.17

where topThree looks like this:

function y = topThree(x)
xs = sort(x,'descend');
y = x(1:min(3,end));

Hope this helps.

Best Answer

Related Solutions

MATLAB: How to have datetime for specific range

MATLAB: How to choose some rows of a table by order

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