Open multiple .WTD files and create a matrix to perform calculation

Hi,

I have 39 .wtd files (see a sample of attached file) and need to read the 1st and 4th columns. Then I need to create a data matrix [0001(:,4) 0002(:,4)...0039(:,4)]. Please help me to create this.

See the 0001.wtd attached.

Thanks for any help in advance.

[Star Strider]

I can’t open it. Also can’t find ‘.wtd’ files in the MATLAB online documentation.

[Damith]

Please unzip it and open in Wordpad or notepad. That's right I could not find too and that's why I need some help.

[Walter Roberson]

Grand Theft Auto files??

[Damith]

I don't understand what u mean.

[Walter Roberson]

When I research what the .wtd file extension is, I find that it is associated with the video game Grand Theft Auto. If that is not the .wtd file extension you mean, you should indicate which tool or file standard your .wtd are fore.

[Star Strider]

I unzipped it to a ‘.wtd’ file, and then couldn’t find an application that would read it. What is it? I suggest you open it and save it as a PDF, then upload the PDF version.

How do you open it in MATLAB? Does it require a specific Toolbox?

Posting the relevant section of code that opens it would help.

[Walter Roberson]

The file is a text file; for example on OS-X I can open it with Text Wrangler without difficulty.

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

all_col1 = [];
all_col4 = [];

then start file loop, and for each

fid = fopen(filename_variable_goes_here, 'r');
col1_4_cell = textscan(fid, '%f%*f%*f%f', 'headerlines', 1, 'CollectOutput', 1);
col1_4 = col1_4_cell{1};
all_col1 = vertcat(all_col1, col1_4(:,1));
all_col4 = vertcat(all_col4, col1_4{:,2));

[Damith]

Thanks for your reply. How can I open all the .wtd files (39 of them). Where does is perform in your code? MY file names are 0001.wtd, 0002.wtd and so on upto 0039.wtd.

What does all_col1 = [] and all_col4 =[]? What is my filename variable?

Please explain since I am new to MATLAB.

Thanks again in advance.

[Walter Roberson]

The line I posted has code outline of how to read a series of files.

all_col1 = [];

initializes a variable named "all_col1" to be the empty matrix. The vertcat() is then used to append information to the bottom of the matrix.

If you use the second batch of code in the link I posted above, the one that reads the file names out of the directory, then filename_variable_goes_here should be changed to fullFileName

[Damith]

I tried your code and all_col1 and all_col4 are empty. Here is the code I tried: I tried reading the attached 0001.wtd file.

all_col1 = []; all_col4 = [];

fid = fopen('0001.wtd', 'r');

col1_4_cell = textscan(fid, '%f%*f%*f%f', 'headerlines', 1,'CollectOutput', 1);

col1_4 = col1_4_cell{1};

all_col1 = vertcat(all_col1, col1_4(:,1)); all_col4 = vertcat(all_col4, col1_4(:,2));