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How to separate the field from a structure in MATLAB?

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SUSHMA MB
SUSHMA MB on 3 Oct 2016
Edited: Stephen Cobeldick on 29 Nov 2020 at 17:25
I have a structure which is attached with this file named as 'shape.mat'. The structure contains the following fields: Geometry Boundary X Y...etc Now i want to separate X and Y field from the structure and store it in a cell named x_constraint and y_constraint respectively. Can it be done?

  2 Comments

Stephen Cobeldick
Stephen Cobeldick on 3 Oct 2016
@SUSHMA MB: You can access the data in the structure quite easily, why not do that?
Siva Priya Bollineni
Siva Priya Bollineni on 21 Sep 2020
@Stephen Cobeldick, I have a matlab file in which i have a class with 4 properties out of which one is a structure with different fields in it. I need to call this matlab file from python through Matlab API engine.
1.Can you please let me know how to access those fields present in that structure of matlab file from python, (when runned the matlab file from python).
2. Also, is there anyway to access the uint64 type data of matlab in to python.
Please someone let me know about this, Thanks in advance.

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Accepted Answer

michio
michio on 4 Oct 2016
Edited: michio on 4 Oct 2016
Your structure seems to be a nonscalar structure, so try using curly bracket:
load('shape.mat');
x_constraint = {S.X};
y_constraint = {S.Y};

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SUSHMA MB
SUSHMA MB on 4 Oct 2016
How can i merge x_constraint and y_constraint into a single cell. I have tried
AllCell = [x_constraint;y_constraint];
But im getting the output as 2x3565cell. As 1x3565cell of x_constraint and y_constraint respectively. Can i get a new cell named 'AllCell' as 1x3565cell, within which the x_constraint and y_constraint are merged into 426X2 double, 64X2 double,.....etc. I hope i made it clear. Please refer the attached file
michio
michio on 4 Oct 2016
One way is to use arrayfun, which applies function to each element of array, in this case, function @(struct) [struct.X; struct.Y] is applied to the each element of a structure S.
load('shape.mat');
AllCell = arrayfun(@(struct) [struct.X; struct.Y], S, 'UniformOutput',false);

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More Answers (2)

Guillaume
Guillaume on 3 Oct 2016
Well, unless I completely misunderstood your question:
x_constraint = yourstructure.X;
y_constraint = yourstructure.Y;
However, there is no benefit to that. Why not use yourstructure.X whenever you want x_constraint and not bother creating x_constraint in the first place?

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SUSHMA MB
SUSHMA MB on 4 Oct 2016
Thank you for the answer. But i tried this too, i am not able to extract the data as shown in the structure. Can you please look into the structure which i have attached with this file and tell me the solution. It gives only the value of first row only.

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Dimas Rizky
Dimas Rizky on 29 Nov 2020 at 15:55
Just type :
x_constraint = shape.X(:,1);
y_constraint = shape.Y(:;1);
I hope it's working for you..

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