create a matrix from a text file

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Hamid Hojaji 2020-12-9

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评论： Hamid Hojaji 2020-12-9

Hi,

I want to create a matrix from a text file,the text file have 3 columns of numbers,first is row number,second is column number and the third column is values.

My program must first read a address of values in first and second column and afterthat put the value from third column in matrix.

What do you suggest?

thanks

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Hamid Hojaji 2020-12-9

It works,thanks a lot.

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Answer 1

Ameer Hamza 2020-12-9

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Try sub2ind(): https://www.mathworks.com/help/matlab/ref/sub2ind.html to convert from row and column number to a linear index. Something like this should work

M = readmatrix('filename.txt');
rows = M(:,1);
cols = M(:,2);
data = zeros(max(rows), max(cols));
ind = sub2ind(size(data), rows, cols);
data(ind) = M(:,3);