Assign rename of structure with input command
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Hello
I am trying to make some of my scripts a bit more easy to use.I am stuck on the rename option of a structure combined with the input command.
What i would like to have is
file=input('Enter the name .dat e.g. "fname.dat" = ')
S = input('Enter a name for the structure = ...')
A=load(file);
S.H1 = A(:,2);
S.H2 = A(:,3);
S.H3 =A(:,4);
Something like that i have but it does not work
how can i finally use the input command in a way that will prompt me and alter the name of the structure?
thank you
采纳的回答
Robert Cumming
2014-8-6
I also do not advocate the use of eval.
You could use "assignin", e.g.
S.H1 = A(:,2);
S.H2 = A(:,3);
S.H3 = A(:,4);
userName = 'ABC';
assignin ( 'base', userName, S ); this assuigns S to the variable name ABC
or put it in a sub function:
function AssignmentFunction ( S, userName )
assignin ( 'caller', userName, S )
end
However I cant really think why you want to do this - if you explain in a bit more detail what your end goal is (how are you using these renamed variables) you will get better help...
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更多回答(2 个)
Evan
2014-8-6
You could use the eval command to do this, but eval can be problematic and usually should be avoided. If you were fine with using nested structures but keep a constant name for the outer structure, you could do this:
S = input('Enter a name for the structure = ...','s')
outerStruct.(S).H1 = rand
This way, you could avoid creating a variable from the string name but still allow some flexibility in structure naming. It would just be a little less neat looking.
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Evan
2014-8-6
编辑:Evan
2014-8-6
This is because you cannot create a variable (in this case a structure) name from a string in that way. You have to use the eval command, which is not recommended. In my example code, I make S the fieldname by using a dynamic field reference, which is why I place the S inside parenthesis.
Another user has submitted an example of how to do this with eval, but I have to agree with him that using it in conjunction with user input is quite risky.
Nir Rattner
2014-8-6
You can use the “eval” function to effectively convert a string to a variable name:
S=input('Enter a name for the structure = ','s');
eval([S '.H1=A(:,2)']);
That being said, “eval” is almost rarely the best choice because it is inefficient and risky (especially when combined with user input). Without knowing exactly what you are trying to do with the renamed struct, another possibility could be to use a wrapper struct and assign the renamed data as one of its fields:
S=input('Enter a name for the structure = ','s');
wrapper.(S).H1=A(:,2);
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