CODEWITHSUNDEEP
matlab
Damien
Damien

Reputation: 43

How to read specific lines with Matlab

Here is what my data file looks like:

1

num   num  num

num   num  num

num   num  num

num   num  num

num   num  num

2

num   num  num

num   num  num

num   num  num

num   num  num

num   num  num

3

num   num  num

num   num  num

num   num  num

num   num  num

num   num  num

. . .

1000

num   num  num

num   num  num

num   num  num

num   num  num

num   num  num

'num' refers to a different float number, and 1,2,3,...,1000 are also part of the file, occupying one line each. What I want to do is, I need a loop from time step 1 to 1000, and during each step, I need to read the 3-column float number block below it as three column vectors. Then I proceed to the next time step, and read the block below, until I finish reading all.

How could I do this file reading with Matlab? In short, what I want to do is to read line 2 to line 6 as a matrix, then line 8 to line 12 as a matrix, then line 14 to 18 as a matrix, and so on...

Thanks!

Upvotes: 0

Views: 1090

Answers (1)

Rotem
Rotem

Reputation: 32084

You can read the text file as follows: 

%Open text file
f = fopen('num.txt', 'r');

num_matrices = 1000;

%Initialize cell array - hold matrices.
C = cell(num_matrices, 1);

for i = 1:num_matrices
    %Read index (to be ignored).
    idx = fscanf(f, '%f', 1);

    %Read 6x3 matrix into A
    A = fscanf(f, '%f', [3, 6])';

    %Store matrix in cell array C.
    C{i} = A;
end

fclose(f);

Refer to https://www.mathworks.com/help/matlab/ref/fscanf.html for fscanf documentation.

Upvotes: 1

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