Another way to do what strsplit does

Question

Sofia Batista 2016-12-17

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https://ww2.mathworks.cn/matlabcentral/answers/317251-another-way-to-do-what-strsplit-does

编辑： Stephen23 2016-12-17

Hello.

What I am looking for is a way to do what strsplit does since my teacher said he didn't know this function and therefore i could not use it. My code so far is

function [n_nos, graph] = Receber1( fich )
f = fopen(fich, 'r');
if f == -1
    disp('Insucesso ao abrir o ficheiro.');
else
    n_nos = 0;
    graph = [];
    while feof(f) == 0
        line = fgetl(f);
        graph(end+1, :) = str2double(strsplit(strtrim(line)));
        n_nos = n_nos+1;
    end
    fechar = fclose(f);
    if fechar == 0
        disp('Ficheiro carregado com sucesso.');
      else
          disp('Insucesso ao fechar o ficheiro.');
          n_nos = -1;
      end
  end
  end

Thank you so much.

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Jan 2016-12-17

在 MATLAB Online 中打开

Tell your teacher:

doc strsplit

Sofia Batista 2016-12-17

Indeed!! I am very restrained because of him and my code is working perfectly but i can't use it.

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Answer 1

Jan 2016-12-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/317251-another-way-to-do-what-strsplit-does#answer_247582

编辑：Jan 2016-12-17

在 MATLAB Online 中打开

The str2double(strsplit(strtrim(.))) is an overkill here, when a simple sscanf does the same already:

function [n_nos, graph] = Receber1( fich )
f = fopen(fich, 'r');
if f == -1  % IMPORTANT: Stop with an error
  error('Insucesso ao abrir o ficheiro: %s', fich);
end
n_nos = 0;
graph = [];
while feof(f) == 0
   line = fgetl(f);
   graph(end+1, :) = sscanf(line, '%f').';   [EDITED]
   n_nos = n_nos+1;
end
fclose(f);  % No test required
end

If the opening of the file fails, stopping with an error is the only secure reaction. Returning without defining the outputs will produce a strange and confusing error message instead.

General rule: Let the code stop in case of an error to avoid running the program in an undefined state with potentially unpredictable effects.

Closing the file can fail under extremely rare conditions only and will not produce any harm. Only if this happens about 250 times, Matlab cannot open files anymore, but this is detected by checking the -1 after fopen already.