vlookup equivalent function in matlab to add data where an input exist

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Locks 2014-9-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/155108-vlookup-equivalent-function-in-matlab-to-add-data-where-an-input-exist

评论： Guillaume 2014-9-17

采纳的回答： Guillaume

Hi,

I have the following problem and did not find any solution that is helping me to get the problem fixed.

First there is the vector with all the dates that exist

dates=[1 2 3 4 5 6 7 8 9 10]'

Now I like to create a 10x3 matrix with the dates as the first column:

dataFinal=zeros(length(dates),3);
dataFinal(:,1)=dates;

That's working fine. Now I'd like to fill this matrix dataFinal with values from other matrices, but only there where the first value of the new matrix (data1 or data 2) is equivalent with the first column of dataFinal

data1=[2 22; 3 24; 4 18; 6 22; 7 25; 9 32]
data2=[1 10; 3 14; 5 19; 6 8; 10 15]

The output should look as follows

dataFinal=[1 0 10; 2 22 0; 3 24 14;4 18 0; 5 0 19 and so on]

I tried to use ismember but I get some problems with the dimensions, because data1 and datafinal do not have the same number of rows

regards

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Answer 1

Guillaume 2014-9-16

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https://ww2.mathworks.cn/matlabcentral/answers/155108-vlookup-equivalent-function-in-matlab-to-add-data-where-an-input-exist#answer_151948

ismember is indeed the function you need:

[found1, ind1] = ismember(dates, data1(:, 1));
[found2, ind2] = ismember(dates, data2(:, 1));
dataFinal(found1, 2) = data1(ind1(found1), 2);
dataFinal(found2, 3) = data2(ind2(found2), 2);

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Locks 2014-9-16

looks good.

can you tell me in addition, how I can plot this without the remaining zeros? in the original dataset the elements of data1 are consecutive dates (2,3,4,5,6 for example) and data2 3,4,5,6,7

so what I am looking for is a line that does not drop to zero

Guillaume 2014-9-17

Please do not post questions in comments but rather start a new question. That way it can be searched and gives someone else the opportunity to get the credit for the answer.

If you don't want to plot the zero, either remove them or replace them with NaN.

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