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How to quickly index the first cell of sets of the array with near similar names?

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Hey all, Here is my workspace:
I want to know if there is any way to index the first cell of each P_ arrays based on (Jan, Feb, Mar,..., Dec, Win, Spr, Sum, Aut, Annual)
For example in this picture I want :
8, 12, 5, 8, 9, 8 , 7, 5, 5, 6, 6, 7, 7, 5, 2, 3, 8
(January to annual)
Thank you all

  1 Comment

Stephen Cobeldick
Stephen Cobeldick on 21 Apr 2020
Bad data design forces you to write slow, complex, obfuscated, buggy code which is hard to debug:
Your code would be simpler and more efficient if you just used a structure, e.g.:
S.Jan = [...]
S.Feb = [...]
...
S.Dec = [...]
Then you could use dynamic fieldnames to access any of the arrays:
fld = 'Jan';
S.(fld)
Or use a table, which would be similarly simple and efficient to access:
Note that you should fix your badly-designed data at the point where those separate arrays are generated in the workspace, e.g. by load-ing into an output variable (which is a scalar structure) instead of directly into the workspace:
S = load(...)

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Accepted Answer

Mehmed Saad
Mehmed Saad on 21 Apr 2020
Edited: Mehmed Saad on 21 Apr 2020
You can do that using eval but it is not efficient to use eval in your code frequently
mn={'Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec','Win','Spr','Sum','Aut','Anuual'};
x = zeros(1,length(mn));
for i=1:length(mn)
x(i) = eval(['P_' mn{i} '(1)']);
end

More Answers (2)

Rik
Rik on 21 Apr 2020
This is bad code design. You should have made these variables fields of single struct. This has forced you to write slow buggy code where you are forced to either write a lot of repetitive code by hand, or use eval. You should change how this data was generated.
Once it is a struct you can use the code below.
fn=fieldnames(P);
output=zeros(size(fn))
for n=1:numel(fn)
tmp=P.(fn{n});
output(n)=tmp(1);
end

KSSV
KSSV on 21 Apr 2020
YOu can get the variable names into a cell and use strcmp to check the variable.
S = whos ;
v = {S.name} ;
idx = strfind(v,'P_Jan') ;

  2 Comments

Behzad Navidi
Behzad Navidi on 21 Apr 2020
Well, Thank you but I'm sorry, I want an entirely different thing. I wanted to index the first value of each array.

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