How to create a vector of symbolic variables with specific labeling

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KostasK
KostasK 2021-9-12
回答： John D'Errico 2021-9-12
I currently have a vector of unevenly spaced increasing values similar to this one:
v = [1 2 3 5 7 9 10 12 18 29]
What I would like to do is create a vector of symbolic variables such that
vsym = [x1 x2 x3 x5 x7 x9 x10 x12 x18 x29]
I know that I can create a function to produce symbolic variables with increasing indices from 1 to 10 lets say by using sym('x', [1 10]), however I am not able to find a way to quickly assign them different indices as I would desire, such as sym('x', v), whee v would be my vector.
Any help would be appreciated

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采纳的回答

Paul
Paul 2021-9-12
Ran in:
v = [1 2 3 5 7 9 10 12 18 29];
vsym = sym('x',[v(1) v(end)]);
vsym=vsym(v)
vsym = 
  2 个评论
Awais Saeed
Awais Saeed 2021-9-12
编辑：Awais Saeed 2021-9-12
Ran in:
It will only work if vector v starts from 1. If vector v starts from 2, let's say, then the results would be different because the syntax requires rows and columns as sym('x', [rows columns]).
v = [2 3 5 7 9 10 12 18 29];
vsym = sym('x',[v(1) v(end)]);
vsym=vsym(v)
vsym = 

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更多回答（2 个）

Awais Saeed
Awais Saeed 2021-9-12
Not the best way but will work good enough for small vectors
vsym = sym('x',size(v));
for col = 1:1:size(v,2)
char_str = ['x' num2str(v(col))];
vsym(col) = sym(char_str);
end
disp(vsym)
I do not know if this could be done more faster.
John D'Errico
John D'Errico 2021-9-12
Ran in:
The simple direct way seems easiest.
v = sym('v',[1 29]);
v = v([1 2 3 5 7 9 10 12 18 29])
v = 

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