How do I designate some variables in the same time that are starting with specific characters?

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HyoJae Lee 2023-3-3

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https://ww2.mathworks.cn/matlabcentral/answers/1922490-how-do-i-designate-some-variables-in-the-same-time-that-are-starting-with-specific-characters

编辑： Stephen23 2023-3-13

采纳的回答： Matthieu

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Hello,

It's a quite simple question.

For example, I have variables named n1, n2, and n3. They have similar names starting with n.

And, those are all cell structure.

I want to exchange this variables into double using cell2mat function.

I want to designate those in the same time and change into double.

I tried

n*=cell2mat(n*)

but, It didn't work.

How can I change this?

Sorry for my bad English. If you have any question regarding this, feel free to ask.

Thanks,

Hyojae.

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Stephen23 2023-3-13

编辑：Stephen23 2023-3-13

"For example, I have variables named n1, n2, and n3. They have similar names starting with n."

Numbering variable names like that is usually a bad data design...

because accessing numbered variable names (like you have) is slow, complex, and inefficient:

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

You should use indexing. Indexing is simple (just as Matthieu showed below) and very efficient.

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Answer 1

Matthieu 2023-3-3

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https://ww2.mathworks.cn/matlabcentral/answers/1922490-how-do-i-designate-some-variables-in-the-same-time-that-are-starting-with-specific-characters#answer_1184675

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Hi,

n = cell(1,3) ; % Replacing your n1, n2, n3 notation with n{1}, n{2}, n{3} 
for i = 1:3
    n{i} = {1,2,3}  ; % Define n{i} cells as you want
end
for j = 1:3        
    n{j} = cell2mat(n{j}) ; % Converting cells to double 
end
n
n = 1×3 cell array
    {[1 2 3]}    {[1 2 3]}    {[1 2 3]}

Is this what you wanted ?

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HyoJae Lee 2023-3-6

Sorry for the late reply!

Appreciate, Matthieu!!

Peter Perkins 2023-3-13

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If n1, n2, and n3 end up being column vectors all with the same length, you might find it useful to put them into a table rather than a cell array. For example, something like

n1 = {1;2;3}; n2 = {4;5;6}; n3 = {7;8;9};
t = table(n1,n2,n3)
t = 3×3 table
     n1       n2       n3  
    _____    _____    _____

    {[1]}    {[4]}    {[7]}
    {[2]}    {[5]}    {[8]}
    {[3]}    {[6]}    {[9]}
t.n1
ans = 3×1 cell array
    {[1]}
    {[2]}
    {[3]}
t = varfun(@cell2mat,t)
t = 3×3 table
    cell2mat_n1    cell2mat_n2    cell2mat_n3
    ___________    ___________    ___________

         1              4              7     
         2              5              8     
         3              6              9     
t.cell2mat_n1
ans = 3×1
     1
     2
     3