MATLAB Central Newsreader - txt2mat

txt2mat

Zahra — Mon, 10 Nov 2008 16:46:03 -0500

Hi all;

I have an ascii file that has a combination of text and data. The text is a header that repeats throughout the file. The data is of the follwoing format where the line is folded for the same data point:

Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74
and so on...

When I use txt2mat, what I get is the follwoing:

[1 v1 v2 v3 v4]
[1 v5 v6 NaN NaN]
[2 v1 v2 v3 v4]
[2 v5 v6 NaN NaN]

What I want instead is a matrix where all the values for the same data point are saved in one row as follows: i.e. avoid the line folding in the final matrix:

[1 v1 v2 v3 v4 v5 v6]
[2 v1 v2 v3 v4 v5 v6]

Any advice as how this can be done is appreciated.

Thanks,
Zahra

Re: txt2mat

Miroslav Balda — Mon, 10 Nov 2008 21:43:02 -0500

"Zahra" <zahra.yamani@nrc.gc.ca> wrote in message <gf9ogb$mrb$1@fred.mathworks.com>...
> Hi all;
>
> I have an ascii file that has a combination of text and data. The text is a header that repeats throughout the file. The data is of the follwoing format where the line is folded for the same data point:
>
> Point v1 v2 v3 v4
> Point v5 v6
> 1 -73 -112 15000 61
> 1 79 79
> 2 -74 -112 25000 61
> 2 72 74
> and so on...
>
> When I use txt2mat, what I get is the follwoing:
>
> [1 v1 v2 v3 v4]
> [1 v5 v6 NaN NaN]
> [2 v1 v2 v3 v4]
> [2 v5 v6 NaN NaN]
>
> What I want instead is a matrix where all the values for the same data point are saved in one row as follows: i.e. avoid the line folding in the final matrix:
>
> [1 v1 v2 v3 v4 v5 v6]
> [2 v1 v2 v3 v4 v5 v6]
>
>
> Any advice as how this can be done is appreciated.
>
> Thanks,
> Zahra

Hi Zahra,

You may try also the function for free format read - ffread,
FEX Id 9034 by calling:

The data file was 'data.txt':
Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74
Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74
Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74

The script for reading it is

ffread('data.txt'); % Initiate Free format reading
first = ffread; % First item of header
A = zeros(100,7); % Estimated size of a matrix A
k = 0;
while first ~= 127 % the end of data?
    ffread(7); % rest of headers
    for j = 1:2
        k = k+1;
        A(k,1:5) = ffread(5);
        ffread; % skip second ident. of point
        A(k,6:7) = ffread(2);
    end
    first = ffread;
end
A = A(1:k,:)

with resulting matrix:

A =
           1 -73 -112 15000 61 79 79
           2 -74 -112 25000 61 72 74
           1 -73 -112 15000 61 79 79
           2 -74 -112 25000 61 72 74
           1 -73 -112 15000 61 79 79
           2 -74 -112 25000 61 72 74

It's all.

Mira

Re: txt2mat

Zahra — Mon, 10 Nov 2008 23:54:01 -0500

Hi Mira,

Thanks for your reply.

The code you sent workd if there is no other headerlines in the file. In my case, the actual data files have teh follwoing format:

-----------------------------------
header1

Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74

header2

Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74

header3

Point v1 v2 v3 v4
Point v5 v6
  1 -73 -112 15000 61
  1 79 79
  2 -74 -112 25000 61
  2 72 74

----------------------------------------------

With this format, when I try your code, I get the follwoing error:

??? Conversion to cell from double is not possible.

Error in ==> ffread at 142
            data(k) = sscanf(st_(nc_:J_(j_)-1),'%e');

Any further advice is greatly appreciated.

Thanks,
Zahra

Re: txt2mat

Andres — Tue, 11 Nov 2008 08:37:02 -0500

Hi there,
I think we've got two parallel threads here. I've posted my reply to http://www.mathworks.com/matlabcentral/newsreader/view_thread/239003
.
Regards
Andres