[Trouble shooting] [MATLAB] Error using unique function; Error using cell/unique. Input A must be a cell array of string

Problem

If the input (A) of unique function contains non-string components, an error occurs.

Check whether the input A contains non-string components or not:

>> A = {'hello';'world';'hello';'young'};
>> unique(A(:,1))
ans = 
    'hello'
    'world'
    'young'

However if the A contains non-string components as like:

>> A = {'hello';[];'hello';'young'};

iscellstr(A(:,1))

ans =

      0

Solution

>> find(cellfun(@(x)~ischar(x),A))

ans =

      2

idxNonString = find(cellfun(@(x)~ischar(x),A));

A(idxNonString,1) = [];

unique(A(:1));