How do I find the mean of certain parts of a cell array?

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Michael Arvin 2022-2-24

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评论： Jan 2022-2-24

Hello. I am trying to find the mean value of certain parts of a cell array. Each cell array row has 8192 values and I am trying to find the mean of each.

A snippet of the cell array:

For example the values of the first 2 rows of the cell array are:

I want to find the mean value of each column from a range of cell array rows 3-10.

Any ideas on how to do so?

Thank you very much!

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Answer 1

Jan 2022-2-24

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编辑：Jan 2022-2-24

在 MATLAB Online 中打开

This is easy, if you store the values in a numerical array instead of a cell. Why do you prefer a cell array?

But you can create the numerical matrix dynamically (although this is not really fast):

% mean value of each column from a range of cell array rows 3-10:
X = mean(cat(1, YourCell{3:10}), 1);

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Michael Arvin 2022-2-24

Got it! Thank you.

Jan 2022-2-24

You are welcome. Finding an efficient representation for the data is a crucial task in programming. Cell arrays are useful, if they contain elements of different sizes or classes. If all have the same size and class, a multi-dimensional array is (usually) better - except if it is huge and a set of smaller arrays would match into the RAM more likely.

Do I use an array of structs or a struct of arrays? Should I use the solution, which uses less memory or is faster to process? On one hand efficient code helps to save minutes of runtime, on the other hand a clean and clear code can avoid hours of debugging. Such questions belong to the work of an experiences programmer. And sometimes the best choice is not to decide for a specific representation, but to keep it flexible for later changes.

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