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How to loop through a series of variables, named with strings but including numbers? -Undefined function or variable

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Niky Taylor
Niky Taylor on 19 Apr 2017
Edited: Stephen Cobeldick on 19 Apr 2017
Hi, I'm an undergraduate researcher trying to figure out how to generate values from a bunch of different datasets. I have 12 matrices from 12 different files, each of which has two fields. The fields in different matrices are the same except for a number tagged onto the end. So the first matrix has fields a_1 and b_1, the second has fields a_2 and b_2, the third has fields a_3 and b_3, etc. I want to multiply the first field of each matrix by the second field of the same matrix and sum it, and I'd like to do this in a loop. Right now I have this:
for i = 1:12; x_i = sum(a_i'*b_i'); A{i} = [i; x_i]; end
I'm trying to get a final matrix A with the numbers 1:12 as field one and the corresponding x value in field 2.
I have very little experience with loops in matlab. Thanks so much for your help!
  2 Comments
Stephen Cobeldick
Stephen Cobeldick on 19 Apr 2017
@Niky Taylor: can you please upload a sample file by making a new comment and clicking the paperclip button. Most likely the best solution would be to import that data into one array, such as an ND array or perhaps a non-scalar structure.
You write that "So the first matrix has fields a_1 and b_1": is the matrix a structure (only structures have fields), or is the matrix numeric type? You write that "12 matrices from 12 different files": are these .mat files, or some other file format?
If you upload your data then we can see exactly what you are trying to explain.

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