Read equations from a text file and create a cell array in MATLAB
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Hello everybody! I have a text file with 8000 equations and I want to create a cell array of 8000x1 for the equations as strings. I have considered textscan for this purpose, but all the equations doesn't have same number of variables and hence I cannot specify the number of columns. How do I go about it? Example:
equations.txt:
1. a=b+c
2. d=e+f+g+h
3. y=2+x*z
4 个评论
Ameer Hamza
2018-5-7
Do you want to only load them as a string? or to also convert them to function handles?
Tiasa Ghosh
2018-5-7
Walter Roberson
2018-5-7
Are the line numbers present in the file? If they are do you want them read in or discarded?
Tiasa Ghosh
2018-5-7
采纳的回答
Walter Roberson
2018-5-7
Provided there are no UNICODE or UTF-8 characters in the file:
filename = 'equations.txt';
S = fileread(filename);
equations = regexp(S, '\r?\n', 'split');
if isempty(equations{end}); equations(end) = []; end %last entry is often empty due to the way regexp split works
If the file does include Unicode that is UTF encoded, then potentially more steps would need to be used to read it properly.
更多回答（1 个）
Ameer Hamza
2018-5-7
编辑：Ameer Hamza
2018-5-7
The following lines will read the lines from the text file and return a cell array of function handles
f = fopen('test.txt');
q = textscan(f, '%s');
fclose(f);
funHandles = cell(1, length(q{1}));
for i=1:length(q{1})
splitAtEqualSign = strsplit(q{1}{i}, '=');
rhs = splitAtEqualSign{2};
funHandles{i} = matlabFunction(str2sym(rhs));
end
3 个评论
Tiasa Ghosh
2018-5-7
Ameer Hamza
2018-5-7
编辑：Ameer Hamza
2018-5-7
Then don't run for loop. q{1} contain cell array of strings.
Ameer Hamza
2018-5-7
Since you mentioned that line numbers are not present. I have updated the answer.
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