Extracting Data from Cells

Dear Matlab users,

I am facing some trouble extracting data from a cell. I attached the a screenshots showing what my cell looks like (cells within a cell). Each cell in the "big" cell has xyz data and i would like to extract each column representing the respective coordinates as column vectors.

My explanation might have been confusing so i will try summarize: Extract the "minor" cells from the main cell, extract the xyz from each minor cell as column vectors.

Thank you for the help

[Guillaume]

What does extract mean? What do you want to do afterward?

[Adam Danz]

I interpreted it as an indexing question.

[Devrim Tugberk]

My goal was the "extract" the xyz coordinates as column vectors and plot them using scatter3()

Answer 1

[madhan ravi]

vv=cellfun(@(x) x(:,1:3),cross_sections,'un',0); % assuming the first three columns in each cell represents x,y & z
v=cat(1,vv{:}); % gathering x,y, & z of each cell into one matrix
scatter3(v(:,1),v(:,2),v(:,3))
%         x -^      ^- y   ^- z

[Devrim Tugberk]

This puts me back to where i started from, maybe my problem wasn't stated properly. At the end, I need to have 3 column vectors for each cell (which represent the xyz respectively). In other words 3 times 138 column vectors with each vector being a coordinate (either x,y or z)

[madhan ravi]

vv would contain the vectors as per your requirement

[Devrim Tugberk]

Okay this script got me the closest so far but my problem with it is that it's plotting ALL of the vectors whereas I want the plot of one single vector xyz to generate the plot of a single cell rather than all of them at once. The point is to be able to analyze each plot individually. I'm sorry i am learning as i go.

[madhan ravi]

for k = 1:numel(vv)
figure(k)
scatter3(vv{k}(:,1),vv{k}(:,2),vv{k}(:,3))
end

[Devrim Tugberk]

Perfect! Thank you all very much

[Devrim Tugberk]

One last tiny tweak, is there a way I could supress the scatter3 function so it doesnt spit out 138 figures? Maybe just give me 138 tables or vectors or something which i can refer back to and plot the desired one only?

[madhan ravi]

Then for instance:

scatter3(vv{2}(:,1),vv{2}(:,2),vv{2}(:,3))

Answer 2

[Adam Danz]

I think this is the format of your data:

C = {rand(20,4),rand(15,4),rand(22,4)}; 

Extract the first 3 columns of cell 2

C{2}(:,1:3)

Extract column 2 of cell 3

C{3}(:,2)

Extract the entire matrix from cell 1

C{1}

Extract the entire matrix from cell 1 but reorganize it into a single column

C{1}(:)

[Adam Danz]

"My goal was the "extract" the xyz coordinates as column vectors and plot them using scatter3()"; " I need to have 3 column vectors for each cell"

@ Devrim Check out the 2nd block of code in my answer. It does what you're describing. If you want to perform that block on all cells,

c3 = cellfun(@(x)x(:,1:3), C, 'UniformOutput', false)

Answer 3

[Guillaume]

If you want to create a scatter3 plot using the coordinates from all the cells of Cross_sections, this is how I'd go about it:

allsections = vertcat(Cross_sections{:});
scatter3(allsections(:, 1), allsections(:, 2), allsections(:, 3));

[madhan ravi]

Probably you meant:

allsections = vertcat(Cross_sections{:});                             

[Guillaume]

Indeed! Otherwise, the operation does nothing.

[Franklin]

Hello All;

I have a 70x1 cell data called info. Inside info is the 1x1 struct, each with 2 variables A and B. index 1.A and 1.B have a size(827x1) while all others 2.A or 2.B...70 are 1348x1.

Am able to extract some portions of "info" e.g. Y_1...Y_5 which I would use for my Y axis on the plot

Q1. How do I plot test1 (Y axis) against X_2(X Axis) without array errors e.g. Arrays have incompatible sizes for this operation.

Q2. How do I get Yall using a Loop or any faster method

Code:

Y_2 = info{2}(:,1).B; % Get Cell 2B data i.e. 1348x1 double

Y_3 = info{3}(:,1).B; % Get Cell 3B data i.e. 1348x1 double

Y_4 = info{4}(:,1).B; % Get Cell 4B data i.e. 1348x1 double

Y_5 = info{5}(:,1).B; % Get Cell 5B data i.e. 1348x1 double

X_1 = info{1}(:,1).A; % Get Cell 1A data i.e. 827x1 double

X_2 = info{5}(:,1).A; % Get Cell 5A data i.e. 1348x1 double

Yall = Y_2...Y_70; % Get all Y values using a loop

test1 = Yall./X_1;

figure(2)

plot(X_2,test1);hold on;

figure(3)

plot(X_1,test1);hold on;