how to arrange data into array

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Tyler 2021-1-7

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https://ww2.mathworks.cn/matlabcentral/answers/711328-how-to-arrange-data-into-array

编辑： Stephen23 2021-1-10

Hi,

i have imported some matrix data into matlab and upon parsing the data i have it in 3 vectors (columns):

column 1 are the row indices (i.e.):

[1;2;3;4]

column 2 are the column indices (i.e.):

[10;11;13;15]

and column 3 are the values in the matrix associated with those indices (i.e.):

[1e-5;5e-5;10e-5;15e-5]

I'd like to arrange this into a single 2-D array of column 3 data in the row locations of column1, and column locations of column2

I could do this with a loop, but im hoping to find a more elegant / less time intensive solution. I have about a million datapoints.

Thanks alot!

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Tyler 2021-1-10

i would use the max row and column indices

Tyler 2021-1-10

turns out i can use the sparse() command, followed by the full() command to achieve my desired outcome.

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Answer 1

Stephen23 2021-1-10

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https://ww2.mathworks.cn/matlabcentral/answers/711328-how-to-arrange-data-into-array#answer_594853

编辑：Stephen23 2021-1-10

在 MATLAB Online 中打开

Without an intermediate sparse array:

R = [1;2;3;4];
C = [10;11;13;15];
V = [1e-5;5e-5;10e-5;15e-5];
%
S = max([R,C],[],1);
M = zeros(S); % or NAN
M(sub2ind(S,R,C)) = V % only the first 10 columns are shown below
M = 4×15
         0         0         0         0         0         0         0         0         0    0.0100         0         0         0         0         0
         0         0         0         0         0         0         0         0         0         0    0.0500         0         0         0         0
         0         0         0         0         0         0         0         0         0         0         0         0    0.1000         0         0
         0         0         0         0         0         0         0         0         0         0         0         0         0         0    0.1500
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