MATLAB: Help clarifying why code isn’t working

matrices

this is my code, and i will attach in the comments what i am trying to portray. I'm having trouble understanding why it wont work. Thanks

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fprintf('%15.4f %15.4f %15.4f %15.4f\n',M(1,:),M(2,:),M(3,:),M(4,:));

Related Solutions

MATLAB: Using non number vectors and number vectors in the same fprintf command (beginner)

There is no good reason to do this in a single fprintf command, and the workaround necessary to do it would be painful. Do this:

fprintf('--------------------\n')
fprintf('%15.4f %15.4f %15.4f %15.4f\n', x',x2',x3',x4')

The reason this is hard is not that you are mixing numbers and text, but that you want a header line different from the rest. fprintf is not designed to do this. If the HW specifies you need it in one fprintf command, give us the exact wording and we may be able to figure out (hopefully) what they are actually asking for or at least why

MATLAB: Using regexp for space delimited strings in text file.

Try this:

% textscan options:
opt = {'MultipleDelimsAsOne',true,'CollectOutput',true};
% required arrays:
str = 'X';
dtv = [];
dat = {};
% open textfile:
fid = fopen('data.txt','rt');
while ischar(str)
    % skip lines until first char is '*' (date vector):
    while ~strcmp(str(1),'*')
        str = fgetl(fid);
    end
    % convert date vector to numeric:
    dtv(end+1,:) =  str2double(regexp(str(2:end),'\S+','match')); %#ok<SAGROW>

    % get file position:
    pos = ftell(fid);
    % read first line of matrix:
    str = fgetl(fid);
    if ischar(str)
        % calculate how many columns in the matrix:
        N = numel(regexp(str(5:end),'\S+','match'));
        fmt = repmat('%f',1,N);
        % rewind one line:
        fseek(fid,pos,'bof');
        % read entire matrix:
        dat{end+1} = textscan(fid,['%4[^*]',fmt],opt{:}); %#ok<SAGROW>
    end
end
% concatenate data in cell arrays:
dat = vertcat(dat{:});
mat = vertcat(dat{:,2});

This reads the entire data matrix (between the date vectors) into a numeric matrix inside the cell array dat, and the date vectors in dtv. It automatically adjusts for the different numbers of columns in your matrices. Some important assumptions:

the first columns comprise of exactly four characters (which may be spaces).
the date vectors always start with asterisks, but no other lines do.
no empty lines between the date vectors and the data matrices.
the matrices contain numeric data only.

Have a look inside dat, and pick the data that you need:

>> cell2mat(cellfun(@(m)m(1,[1,2,3]),dat(:,2),'UniformOutput',false))
ans =
   1.0e+04 *
    0.6445   -2.4080   -0.8935
    0.6645   -2.2892   -1.1498

I also concatenated the matrices into mat, which lets gives you all of the matrices in one. This might be easier to access:

>> mat([1,10],[1,2,3])
ans =
   1.0e+04 *
    0.6445   -2.4080   -0.8935
    0.6645   -2.2892   -1.1498

I tested this code on both of the files that you have provided (this question, and your last question), which are also available here:

Best Answer

Related Solutions

MATLAB: Using non number vectors and number vectors in the same fprintf command (beginner)

MATLAB: Using regexp for space delimited strings in text file.

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