How to create nested tables

I have the following code which creates a 3x3 table using some dummy data:

numsmall = [5; 3; 8];
nummedium = [26; 53; 81];
numbig = [316; 582; 711];
numtable = table(numsmall, nummedium, numbig);

I would like to store 'numtable' in another table, but I would like to also 'compress' it down to one element.

mastertable = table(numtable);

This results in the following:

However I would like to have '3x3 table' in the (1,1) box instead. In other words, I want to store that 3x3 table into that (1,1) box in my 'mastertable'.

I'm planning to put another 3x3 table into the (2,1) box when I receive that data in the future.

What changes do I need to make to my code?

[Stephen23]

"What changes do I need to make to my code?"

Make that column a cell array, then you can store whatever you want in each cell.

[Paul]

@Darrian Low

What is the benefit of nesting tables in cells in a table instead of putting the tables a cell or structure array?

[Darrian Low]

I was looking to store numerous tables into another table or some other format to avoid having numerous tables in my workspace. The thought of having tables in a cell or structure didn't cross my mind!

[Paul]

Storing each table as an element of another container array makes it easy to access each table individually. If each tble has the same structure, then it's easy to combine them (or subsets of them) and perform operations on them using arrayfun/cellfun/structfun.

For example:

numsmall = [5; 3; 8];
nummedium = [26; 53; 81];
numbig = [316; 582; 711];

Store two tables with same format in a struct array

s(1).numtable = table(numsmall, nummedium, numbig);
s(2)=s(1);

Combine into a single table if we want to operate on all of the data

allT = vertcat(s.numtable)

allT = 6×3 table
    numsmall    nummedium    numbig
    ________    _________    ______

       5           26         316  
       3           53         582  
       8           81         711  
       5           26         316  
       3           53         582  
       8           81         711  

Use arrayfun to apply the same operation to each table. Using varfun here to get the sum of the columns in each table, but could be anything of use, e.g., plot

C = arrayfun(@(s) varfun(@sum,s.numtable),s,'Uni',false)

C = 1×2 cell array
    {1×3 table}    {1×3 table}

Combine those results if desired

sumT = vertcat(C{:})

sumT = 2×3 table
    sum_numsmall    sum_nummedium    sum_numbig
    ____________    _____________    __________

         16              160            1609   
         16              160            1609   

etc.

Answer 1

[dpb]

numsmall = [5; 3; 8];
nummedium = [26; 53; 81];
numbig = [316; 582; 711];
numtable = table(numsmall, nummedium, numbig);
mastertable = table({numtable})  % store as a cell in another table

mastertable = table
       Var1    
    ___________

    {3×3 table}

You can dispense with the temporary...

clear mastertable  % just to make it clear is new one
mastertable = table({table(numsmall, nummedium, numbig)})

mastertable = table
       Var1    
    ___________

    {3×3 table}

Remember you will have to dereference the cell with the {} to be able to address it.

mastertable.Var1

ans = 1×1 cell array
    {3×3 table}

only returns the content of the cell which is a cell still...

 mastertable.Var1{1}

ans = 3×3 table
    numsmall    nummedium    numbig
    ________    _________    ______

       5           26         316  
       3           53         582  
       8           81         711  

returns the content of the cell from which can then get the data.

 mastertable.Var1{1}.numsmall

ans = 3×1

5 3 8

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