findgroups error class variable not supported

I have a cell array, 'finalData'' and trying to use the findgroups command to sort it but i keep getting the error:

I dont have any cells in 'finalData' that appear to be cells. is there an easy way to trouble shoot?

Error using matlab.internal.math.grp2idx (line 125)

A grouping variable of class 'cell' is not supported.

Error in matlab.internal.math.mgrp2idx (line 64)

[ogroup,gnum,gdata{1}] = matlab.internal.math.grp2idx(group{1,1},inclnan,inclempty);

Error in findgroups (line 88)

[gnums,~,gnames] = matlab.internal.math.mgrp2idx(groupVars,0,inclnan,inclempty);

Error in STK_LEO_OP (line 185)

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

Answer 1

[Yongjian Feng]

You can type help findgroups from command line window. It show what input argument findgroups is expecting:

G = findgroups(A) returns G, a vector of group numbers created from the
    grouping variable A. G contains integer values from 1 to N, indicating
    N distinct groups for the N unique values in A.
 
    A is a categorical, numeric, logical, string, datetime, duration,
    or calendarDuration vector, or a cell array of character vectors.
    G has the same length as A.

Any other kind of A can generate an error you saw.

[Qiana Curcuru]

I think what im looking for is a command that can tell me which items in the matrix are cells so i can figure out how to make them compatible

Answer 2

[Walter Roberson]

I have a cell array, 'finalData''

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

When you use () indexing with a cell array, the result is a cell array. You might need to

    [G, fields] = findgroups(finalData{:,1});

However, if you have multiple entries in the cell, then a question arises as to whether you want to find the groups over all of the entries, or if instead you want to find groups per-entry. If you want to find groups per-entry then

     [G_cell, fields_cell] = cellfun(@findgroups, finalData(:,1));