Creating a variable from part of a string

Question

Benjamin 2018-11-7

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/428570-creating-a-variable-from-part-of-a-string

编辑： Stephen23 2018-11-7

采纳的回答： Stephen23

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I have a string:

x='dr_1e-2_A1_OFF_A2_OFF.txt';

Is there a way to create variables from this string?

How can I set

dr = 1e-2

by only referring to the string? How can I set

A1 = 0 (since Off)

by only referring to the string?

Then if I want to create a title from the variables, could I?

Like:

title('dr = ' insert dr variable )

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Stephen23 2018-11-7

"Then if I want to create a title from the variables, could I?"

You certainly could... but this is not recommended. Magically creating variable names is one way that beginners force themselves into writing slow, complex, buggy code which is hard to debug. Read this to know why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

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Answer 1

Stephen23 2018-11-7

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/428570-creating-a-variable-from-part-of-a-string#answer_345713

编辑：Stephen23 2018-11-7

在 MATLAB Online 中打开

I recommend that you use a structure instead of magically accessing variable names:

>> x = 'dr_1e-2_A1_OFF_A2_OFF.txt';
>> [~,N] = fileparts(x);
>> C = regexp(N,'_','split');
>> S = struct(C{:});
>> S.dr
ans = 1e-2
>> S.A1
ans = OFF
>> S.A2
ans = OFF

You can easily add a conversion to numeric as well:

>> [~,N] = fileparts(x);
>> C = regexp(N,'_','split');
>> V = str2double(C);
>> X = ~isnan(V);
>> C(X) = num2cell(V(X));
>> S = struct(C{:});
>> S.dr
ans = 0.010000