MATLAB: Is it possible to read a file line by line and then break each line into individual characters/numbers for further processing

MATLAB

If I have a file with the folliwing contents:

a file.dat
a
n pqr 3 2
1 -3 0
2 3 -1 0

Then is it possible to extract the numbers like 3 and 2 when I read the first line? Also, breaking the string in the set of numbers that are separated by spaces except for the pqr. The lines with numbers will be terminated always by '0'. So I would need to get the following result

k = 3

m = 2

j1 = [1 -3]

j2 = [2 3 -1] as the matrix.

Rest all characters are not needed to be read.

Best Answer

If the txt file follow the same format then try the following code

data = strsplit(fileread('data.txt'), newline);
mn = textscan(data{3}, '%s %s %f %f');
m = mn{3};
n = mn{4};
j1 = sscanf(data{4}, '%f');
j1(end) = [];
j2 = sscanf(data{5}, '%f');
j2(end) = [];

data.txt is attached.

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MATLAB: Connecting line

added after your code

hold on
k = reshape([3 2 1 5 6 4],3,[]);
arrayfun(@(i1)plot3(Num(i1,k(1,:)),Num(i1,k(2,:)),Num(i1,k(3,:))),1:size(Num,1))

MATLAB: Cursor line

This can be done with a little handle graphics. I don't have time right now to make this code perfect (error checking, special cases handling, commenting(!), etc.), but it should give you something of an idea. Run this function then hit the left and right arrow to see what happens.

function [] = data_subplots()
% Link data cursors so that they track accross subplots.
% Create the subplots.
% Alternatively, use GET to create s and L from existing plots.
x = 1:.1:10;
for ii = 1:3
    s(ii) = subplot(3,1,ii);
    L(ii) = plot(x,sin(x/ii)*ii);
end
% Now start the work.
for ii = 1:length(s)
    S.D{ii} = get(L(ii),{'xdata','ydata'});
    S.L(ii) = length(S.D{ii}{1});    
    S.M(ii) = floor(S.L(ii)/2);
    S.DF = diff(S.D{ii}{1}(S.M(ii):S.M(ii)+1)); % uniform assum
    S.I(ii) = S.M(ii);
    S.T(ii) = text(S.D{ii}{1}(S.M(ii)+2),S.D{ii}{2}(S.M(ii)+2),'here');
    set(S.T(ii),'string',{['X: ',sprintf('%3.3g',S.D{ii}{1}(S.M(ii)))];...
        ['Y: ',sprintf('%3.3g',S.D{ii}{2}(S.M(ii)))]},...
        'parent',s(ii),'backgroundco',[.8 .8 0]);
    set(s(ii),'nextplot','add')
    S.F(ii) = plot(s(ii),S.D{ii}{1}(S.M(ii)),S.D{ii}{2}(S.M(ii)),'sk');
    set(S.F(ii),'markerfacec','b')
end
set(gcf,'keypressfcn',{@fh_kpfcn,S})
function [] = fh_kpfcn(varargin)
D = varargin{2}.Key;
S = varargin{3};
if strcmp(D,'leftarrow')
    for ii = 1:length(S.T)
        if S.I(ii)~=1
            S.I(ii) = S.I(ii)-1;
            set(S.F(ii),'xdata',S.D{ii}{1}(S.I(ii)),...
                'ydata',S.D{ii}{2}(S.I(ii)))
            set(S.T(ii),'position',...
                [S.D{ii}{1}(S.I(ii))+S.DF*2,S.D{ii}{2}(S.I(ii))],...
                'string',{['X: ',sprintf('%3.3g',S.D{ii}{1}(S.I(ii)))];...
                ['Y: ',sprintf('%3.3g',S.D{ii}{2}(S.I(ii)))]})
        end
    end
elseif strcmp(D,'rightarrow')
    for ii = 1:length(S.T)
        if S.I(ii)~=S.L(ii)
            S.I(ii) = S.I(ii)+1;
            set(S.F(ii),'xdata',S.D{ii}{1}(S.I(ii)),...
                'ydata',S.D{ii}{2}(S.I(ii)))
            set(S.T(ii),'position',...
                [S.D{ii}{1}(S.I(ii))+S.DF*2,S.D{ii}{2}(S.I(ii))],...
                'string',{['X: ',sprintf('%3.3g',S.D{ii}{1}(S.I(ii)))];...
                ['Y: ',sprintf('%3.3g',S.D{ii}{2}(S.I(ii)))]})
        end
    end
end
set(gcf,'keypressfcn',{@fh_kpfcn,S})  % Update the structure.

Best Answer

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MATLAB: Connecting line

MATLAB: Cursor line

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