Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Re: Difficulty reading specific information from a .txt file
Posted:
Mar 25, 2013 4:04 PM


On Tuesday, March 26, 2013 8:49:06 AM UTC+13, Miguel wrote: > I'm having trouble reading certain specific information from a .txt file. This contains a 48x48 matrix (element stiffness). Each entry is preceded by the row and colomn information like [ row, colomn]: > > > > I'd like to generate a 48x48 matrix on matlab removing everything that is not an entry value from the text file. > > > > A segment of the matrix is for example: > > Matrix: > > [ 1, 1]: 1.220e+002 [ 1, 2]: 4.688e+001 [ 1, 3]: 1.220e+002 [ 1, 4]: 0.000e+000 ... > > [ 2, 1]: 4.688e+001 [ 2, 2]: 7.754e+001 [ 2, 3]:7.353e+000 [ 2, 4]: 0.000e+000 ... > > [ 3, 1]: 1.220e+002 [ 3, 2]:7.353e+000 [ 3, 3]:1.811e014 [ 3, 4]: 0.000e+000 ... > > [ 4, 1]: 0.000e+000 [ 4, 2]: 0.000e+000 [ 4, 3]: 0.000e+000 [ 4, 4]: 0.000e+000 ... > > ... > > > > When the values are positive there's a space between the ]: part and the number. Example:[ 2, 1]: 4.688e+001 > > > > The main issue is the negative values where the space has been replaced with a minus sign like for example: [13, 1]:4.023e+000. I don't know in advance where the negative values are located. > > > > The code I have so far goes like: > > > > fid = fopen('Stiff_elem.txt'); > > D = textscan(fid, '%s',1);% Jumps first line > > for i=1:48 > > C{1,i} = textscan(fid, '%s',N); > > end > > fclose(fid); > > > > When collection the information with textscan I've been unable to obtain the negative values without collecting the colomn number and ]: as well which means N varies from row to row and therefore I don't know which entries of D contain the important information. > > > > Does anyone know how to solve my problem? > > > > Thanks in advance for the attention!
Why not use : as the delimiter: fmt=repmat('%s%f',1,48); % Read each row completely c=textscan(fid,fmt,... 'delimiter',':',... 'headerlines',1); Now c will contain the whole matrix, including the [..]s which you can discard.



