reshaping data so that I can take sum of every 3 columns

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

Answer 1

[Kelly Kearney]

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.

[Neesha]

Perfect, thanks a lot! It is dataset , not an array but it does work for me...

Answer 2

[Jacky Jo]

Is that you want..

saleCost=[5, 7, 9 , 2, 5, 1, 9, 11, 1;...
  12, 9, 2, 3, 5, 10, 11, 4, 4;...
  20, 2, 2, 3, 20, 30, 1, 3, 7;...
   1, 9, 3, 33, 22, 10, 6, 6, 8];
saleCost=reshape( reshape(saleCost',[],3) ,3,[]);
saleCost=reshape(sum(saleCost,1),3,[])'

[Neesha]

Let me try what is the result. I do not want to lose context info i have as i have shown in resultant set.

[Neesha]

It did not work, first line created all in one row with bunch of data added with default values. Also as i tried to execute second row, it ran into memory error