How to match data from two separate variables, then extract it as a new variable?

Question

Skyler Mallozzi 2018-6-11

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回答： Kaninika Pant 2018-6-13

I'm working with two variables where the first column is time as a decimal number, then a second column with my data shown as such:

Let's call these variables A and B. I need to match the decimal times from the first column of both variables, then extract the resulting times and the data attached to those times. So the result can either be:

ResultingVariableA = [MatchedTimes;A_MatchedTimes] and ResultingVariableB = [MatchedTimes;B_MatchedTimes]
ResultingVariable = [MatchedTimes;A_MatchedTimes;B_MatchedTimes]

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Paolo 2018-6-12

编辑：Paolo 2018-6-12

Can you attach the mat file?

Skyler Mallozzi 2018-6-12

2018-05-03-Valentine.mat

The variables are May_3_BaseMag and May_3_Center

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Answer 1

KSSV 2018-6-12

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You need to go for interpolation......you need to interpolate both the data to common time stamps. Have a look on interp1

https://in.mathworks.com/help/matlab/ref/interp1.html

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Answer 2

Kaninika Pant 2018-6-13

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在 MATLAB Online 中打开

One way of achieving this is by using the ismember function. You can read about it here:

https://www.mathworks.com/help/matlab/ref/ismember.html

I am attaching a simple program to illustrate how you may work with this:

    A=[ 1,45;
    2,56;
    3,89;
    3,89;
    4,66;
    5,23;
    5,55]
    B=[3,77;
    3,88;
    5,90;
    5,100;
    6,78]   %note that there are repetitions in this data
   [common,loc]=ismember(A(:,1),B(:,1))  %common: logical array(entry=1 wherever element of A is present in B.)
% Note that loc has the "smallest" index in B where this common value is present. 
x=[];
for i=1:length(A)
    if common(i)
        if ismember(A(i,1),x)   %if this is a repeated entry 
            loc(i)=loc(i)+count;  %I had to do this since loc only stores the smallest index and there is repetition in your data.
            count=count+1;
        else
            count=1;
        end
        x=[x;A(i,1),A(i,2),B(loc(i),2)];  %x is the final array you desire
    end
end