MATLAB Answers

reading a huge matrix which is split to several parts

2 views (last 30 days)
Jan Pavlik
Jan Pavlik on 21 Aug 2020
Commented: Jan Pavlik on 24 Aug 2020
Dear all,
is there a simple way in MATLAB to read a matrix from a text file, when the matrix is too wide to span the linewidth and is therefore split to consecutive parts? An example file is attached.
I will be thankful for any advices.

Accepted Answer

per isakson
per isakson on 22 Aug 2020
Edited: per isakson on 22 Aug 2020
The text file contains column and row numbers together with blocks of the matrix. These row and column numbers can be used for checks and to find the number of columns of each block. In my script below, I assume that all the blocks contains four columns. And there is no error checking in my script.
chr = fileread('matrixsample.txt');
chr = strrep( chr, char(13), '' ); % simpler without carrige return
str = string( chr );
[ blocks, matches ] = strsplit( str, '(?m)^[\d\x20]+$' ...
, 'DelimiterType','RegularExpression' );
blocks(1) = []; % first line is a delimiter
cac = cell( 1, numel(blocks) );
for bb = 1 : numel(blocks)
cac(bb) = textscan( blocks(bb), '%*d%f%f%f%f', 'CollectOutput',true );
num = cell2mat( cac );
The result is in num
>> whos num
Name Size Bytes Class Attributes
num 8x8 512 double

  1 Comment

Jan Pavlik
Jan Pavlik on 24 Aug 2020
Dear per isakson, thank you very much, this indeed works :)

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!