How do you import an txt file with text, numbers, and varying columns in each row?

I have a txt file (extract attached) from which I need to collect all the numerical values. I have used the dlmread, readmatrix, load, and importdata functions all with no success. When using the load function:

k_input = load('Element Stiffness Matrices 1.txt');

I get the following error: "Number of columns on line 2 of ASCII file Element Stiffness Extract.txt must be the same as previous lines." When using the importdata function:

k_input = importdata('Element Stiffness Matrices 1.txt');

The textdata file formed only contains text from the first few rows of the txt file. The txt file gives stiffness matrices, outputted from FE software Abaqus. I am trying to create an autonomous code that reads this data into matlab so manual intervention will not be possible. The full file is very large (nearly 500,000 lines with over 5000 repeats of data similar to that in the extract) and can be reduced to a sixth of the size but no smaller, which would still leave a very large file.

Any help would be appreciated, thanks for your help in advance.

[Star Strider]

That file is likely going to be a challenge, at least in part because of all the blank entries.

The fileread function may be the best option, however that still requires that the data be put in some sort of format that MATLAB can use. That is less than obvious.

What is the output supposed to be? What is it supposed to look like?

[Leo Cordery Smith]

Thank you for the response. The numbers in the extract form a lower triangular matrix for the stiffness of a single finite element. I have code that will convert the numbers into the desired format, the problem is importing the file into matlab in the first place. Ideally MATLAB will read the numbers and put them into a nx2 matrix as it does when I manually remove the text in the file and use the importdata function. However, this manual operation is not suitable as I would have to do it for all 850 elements in the full file. So I either want to import the file without the text, or import the whole file and remove the text using additional code.

[Star Strider]

My pleasure.

It is still not obvious to me how to create or re-format that as a matrix of any sort.

[Leo Cordery Smith]

After the *MATRIX,TYPE=STIFFNESS text the matrix begins. The first line has 1 element, the second has 2, the third has 3 and so on. The txt file only shows 4 elements per line so it starts a new one if needed. For example, the fifth line that starts with 12443045210.925 loops onto another line but a new row begins after 44533380477.756. Do you not see a way in which I can at least import just the numerical data only?

[Star Strider]

Do the lines with one entry and then three blank coilumns mean anything?

It can likely be read as a text file, however iis still not obvious to me how to parse that into anything meaningful.

[Leo Cordery Smith]

Yes, they are stiffness values carried over from a row as explained above. My code populates a matrix using these stiffness values as such:

A = [1; 2 3; 4 5 6; 7 8 9 10; ...] where the numbers represent the order in which values appear in the txt file. For line 5 of that A matrix, there are 5 values and with the txt file only holding 4 values per line, it loops round before starting another line for the next column. But like I said, that part of the code is good, I just need to get the txt file into matlab in the first place without manually editting it beforehand. The standard read functions (as listed above) give me errors, I'm hoping that someone can tell me which one will work with the correct syntax.

[Alex Alex]

try function "textscan" and begin work with this information....

fileid=fopen('Element Stiffness Matrices 1.txt')

C = textscan(fileid,'%s ','Delimiter','\b','CommentStyle','*');

[Mario Malic]

I have a better question,

How do you export this file? Do you have some settings to choose? I think I have seen some files, that do not "break the line" by going into the next line, which would be helpful in your case. How big is the file, could you output the complete stiffness matrix, this would save you a lot of coding effort.

Answer 1

[Harikrishnan Balachandran Nair]

From my understanding, you are facing an issue in importing a text file, with varying number of columns in each row. The possible workaround for this would be to use the textscan function in Matlab to import the text file into your workspace.

fin = fopen( 'Element Fitness Extract.txt' ); 
output = textscan( fin, '%s%s%s%s', 'CollectOutput'  ,   true, 'Delimiter', ','  );