How to create a matrix from a txt file with variable column numbers?

Question

Diogo Nascimento 2016-4-11

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/278455-how-to-create-a-matrix-from-a-txt-file-with-variable-column-numbers

评论： Diogo Nascimento 2016-4-12

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

Hey there!

I am trying to create a matrix from a txt file that the user inputs that goes like this:

Matrix
4
    1  1  3  2  6  1
    2  1  4  3  5  2  5
    3  1  3  4  8  3
    4  1  3  5  1  6

The number in the line after "Matrix" represents the number of lines of the matrix I wanna create.

The number of the 3rd column represent the remaining entries on that line and can only vary between 3 or 4.

I've come up with

tline = fgetl(file);
n = fscanf(file,'%f',1);
matrix = fscanf(file,'%e', [n inf]); % but this puts it into a 1x... Matrix...

Thanks for the help

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Jan 2016-4-11

What result do you want? A matrix is rectangular by definition.

Diogo Nascimento 2016-4-12

I want to fill the shorter rows with zero, to make it rectangular

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Answer 1

Walter Roberson 2016-4-12

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/278455-how-to-create-a-matrix-from-a-txt-file-with-variable-column-numbers#answer_217495

在 MATLAB Online 中打开

tline = fgetl(file);
n = fscanf(file, '%f', 1);
for K = 1 : n
   rownum = fscanf(file, '%f', 1);
   col_offset = fscanf(file, '%f', 1);
   num_ent = fscanf(file, '%f');
   data_for_row = fscanf(file, '%f', [1 num_ent]);
   data(rownum, col_offset + (0:num_ent-1)) = data_for_row;
 end