grouping like items in column

I have a cell array that looks like:

a={apples} {1}
  {orange} {2}
  {apples} {3}
  {Pear}   {4}
  {apples} {5}
  

I want to get like items together in their own matrix like:

a1= {apples} {1}
    {apples} {3}
    {apples} {5}
a2= {orange} {2}
a3= {pear}   {4}

Thank you!

Answer 1

[Matt J]

One way:

a=sortrows(a,1)

[Qiana Curcuru]

thanks that's almost what i want.

After they are sorted, i want to set each like row to its own variable like i have above.

[Matt J]

That would be a bad idea:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

The better thing to do would be to organize the subsets of a as fields of a struct:

a={'apples',1;...
    'orange',2;...
    'apples',3;...
    'Pear',4;...
    'apples',5};
  

[G,fields]=findgroups(a(:,1));

X=splitapply(@(x){x.'}, a(:,2),G);

Sa=cell2struct(X,fields)

Sa = struct with fields:
      Pear: {[4]}
    apples: {[1]  [3]  [5]}
    orange: {[2]}

[Qiana Curcuru]

awesome thanks! so then how would you reference items in the struct?

Like if i wanted to know what objects are under 'apples' what is the command for that?

[Walter Roberson]

Sa.apples

[Qiana Curcuru]

ah okay, but what if i dont know what the categories are since i am writing them with a for loop. is there a way to refernce them using indices?

[Matt J]

You should use dynamic field referencing.

fields=fieldnames(Sa);

for i=1:numel(fields)

    Sa.(fields{i})
    
end