How to access column of double in struct array?

Hi good people!

I have a shp file (coastlines.shp) and need to get the lat, long and date data that are in the x, y and date (multiple data points) columns in double format and turn them into matrix data. Every time I try to access, I can only get the data from the first line or specific line, I've tried several ways, but without success.

Could be help me?

[VBBV]

x(i,:) = 
y(i,:) =
Date(i,:) = 
% rename date in output vector to Date as its already used in the struct

Use the above format as shown which uses the for loop index.

[Stephen23]

The MATLAB approach would be to use comma-separated lists:

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

But note that all of the X and Y vectors have different lengths: so far your indexing shows that you have not taken this into account. Before you start trying to join them all together, you need to decide how you want to concatenate vectors of different sizes together.

"How to access column of double in struct array?"

None of X and Y are columns vectors, so it seems there might be some confusion about sizes.

[Cícero Vicente]

Hi Stephen23

Exactly. That's another question: X, Y and date have different sizes in their vectors, I believe that's why I can't access them. I need a code or solution that accesses the vectors, with their different sizes, and turns them into arrays of columns or something similar. I tried with the 'getfiled' function and other ways, but without success.

Can you help me?

Answer 1

[Stephen23]

"...and turn them into matrix data"

"Can you help me?"

Download this:

https://www.mathworks.com/matlabcentral/fileexchange/22909-padcat

and then use it like this:

X = padcat(coast.X)
Y = padcat(coast.Y)

For the dates use a cell array:

D = {coast.date}

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

[Cícero Vicente]

Stephen23,

Thank u for your help!

I managed to do what I wanted: "how to access column of double in struct array". Now I will work with the data. Thanks.

Answer 2

[VBBV]

x(i,:) = 
y(i,:) =
Date(i,:) = 
% rename date in output vector to Date as its already used in the struct

Use the above format as shown which uses the for loop index.