Creating a variable referencing specific cells from a cell variable with 30 structures?

I have a variable that I converted to a cell. This variable is a 1x30 cell with 30 structures within it. (I had multiple levels) Each structure is a set of data (3000x20).

I want to create a new variable that contains that 3000th row, 1st column from each of those structures (3000,1).

I've tried X = Variable30Structures {:,1}{3000,1} However I get a message "matlab Expected one output from a curly brace or dot indexing expression, but there were 30"

I'm sure there is a simple way to do this, but I'm stuck as I've never tried this before.

Any help would be appreciated! Thank you

[Stephen23]

You write that "This variable is a 1x30 cell with 30 structures within it", but then your example does not refer to any structure field: is this an actual MATLAB structure, or are you using the word "structure" just to describe "some organization of data" ? If it really is a structure, what fieldname is required to access that data?

"I have a variable that I converted to a cell"

Why? What form did the data have beforehand?

Answer 1

[Stephen23]

Assuming that by "structure" you really just mean "array", and C is your cell array, then this might work for you:

tmp = cat(3,C{:});
out = tmp(3000,1,:)

You should read these too, they explain why your attempt does not work:

https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists

https://www.mathworks.com/matlabcentral/answers/344486-generate-comma-separated-list-in-single-line-of-code