MATLAB: Reshaping data so that I can take sum of every 3 columns

MATLAB

Hi All,
I have a dataset something similar to following
   Name     Location     Nickname     saleCost
   rest1    east         Reast1       [5, 7, 9 , 2, 5, 1, 9, 11, 1]
   rest4    south        Rsouth4      [12, 9, 2, 3, 5, 10, 11, 4, 4]
   rest3    east         Reast3       [20, 2, 2, 3, 20, 30, 1, 3, 7]
   rest9    west         Rwest9       [1, 9, 3, 33, 22, 10, 6, 6, 8]
Note that saleCost is a dataset as well and as number of columns which are multiple of 3.
I want to add up every 3 columns so my resultant dataset is as follow
     Name     Location     Nickname     saleCost
     rest1    east         Reast1       [21, 8, 21]
     rest4    south        Rsouth4      [23, 17, 19]
     rest3    east         Reast3       [24, 53, 11]
     rest9    west         Rwest9       [13, 65, 20]
I tried using reshape() but could not use it correctly. WHat are my options?
Thanks

Best Answer

When you say you have a dataset, do you mean a dataset array? I'm assuming so for the moment:
Your data:
tmp = {...
   'Name'    'Location'     'Nickname'     'saleCost'
   'rest1'    'east'         'Reast1'       [5, 7, 9 , 2, 5, 1, 9, 11, 1]
   'rest4'    'south'        'Rsouth4'      [12, 9, 2, 3, 5, 10, 11, 4, 4]
   'rest3'    'east'         'Reast3'       [20, 2, 2, 3, 20, 30, 1, 3, 7]
   'rest9'    'west'         'Rwest9'       [1, 9, 3, 33, 22, 10, 6, 6, 8]};
D = cell2dataset(tmp);
Reshape:
D.saleCost = reshape(sum(reshape(D.saleCost', 3, []),1), [], size(D.saleCost,1))'
D = 
      Name           Location       Nickname         saleCost                  
      'rest1'        'east'         'Reast1'         21           8          21
      'rest4'        'south'        'Rsouth4'        23          18          19
      'rest3'        'east'         'Reast3'         24          53          11
      'rest9'        'west'         'Rwest9'         13          65          20
Pretty much the same as Jelin's answer, but all in one command. Note that this applies to the entire array saleCost; you shouldn't need to loop over rows.
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