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April 22nd, 2008

MATLAB Basics: Array of structures vs Structures of arrays

This short video covers the difference between a “structure of arrays” and an “array of structures”.

Video Content

12:28 pm | Posted in MATLAB Basics, PodCast, Video | Permalink |

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4 Responses to “MATLAB Basics: Array of structures vs Structures of arrays”

1. Emil replied on April 22nd, 2008 at 1:54 pm :
   

   It’s easier to create vector s by:
   s = [people.SimmNum];

2. Tom replied on April 22nd, 2008 at 4:29 pm :
   

   This and Emil’s comment were quite helpful to me.

   To take this one step further, one advantage of Arrays of Structures would be the ability to have vectors of different lengths for each numerical part, and a cell array of names of different lengths for each name part.

   For example:

   people(1).name=’Erin’
   people(2).name={’Joan’ ‘Carla’}
   people(1).sim=44
   people(2).sim=[561 49]

3. Doug replied on April 23rd, 2008 at 8:01 am :
   

   Emil,

   Yes, you are correct. I can not believe I over looked that. There are so many ways to do certain things in MATLAB.

   Doug

4. Ryan Gray replied on April 24th, 2008 at 2:31 pm :
   

   If you have an array that you want to assign to a field across a structure array, you can do this:

   [structArray(:).fieldname] = deal(num2cell(array))

   Of course, the length of array should be the same as the length of structArray, but if structArray doesn’t exist yet, then you can do:

   [structArray(1:length(array)).fieldname] = deal(num2cell(array))

   If array is already a cell array, you can avoid using both deal and num2cell (although they will still work) and use:

   [structArray(:).fieldname] = array{:}
   or
   [structArray(1:length(array)).fieldname] = array{:}

   An example, modifying the struct array ‘people’ from the video:

   names = {’Larry’,'Moe’,'Curly’};
   [people(:).name] = names{:};

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