Converting table column of cell arrays to column with comma separated values

I have a table where most columns are single values, but two columns are cells that contain multiple values (e.g., 3x1, 4x1, 5x1 cells). I need to convert these columns of cells to columns with comma separated values, so that {'2'} {'3'} {'4'} becomes '2,3,4'. Many rows contain all empty [] cells, and these need to be preserved.

The end goal is that this table needs to be written to a .xlsx file, where the columns with multiple values have all values in a single cell, separated by commas.

Answer 1

[Stephen23]

A = [11;22;33;44;55];
B = {{'1'};{'2';'3';'4'};[];{'6';'7'};{'8'}};
T = table(A,B)

T = 5×2 table
    A          B      
    __    ____________

    11    {1×1 cell  }
    22    {3×1 cell  }
    33    {0×0 double}
    44    {2×1 cell  }
    55    {1×1 cell  }

X = ~cellfun(@isempty,T.B);
T.B(X) = cellfun(@(c)join(c,','),T.B(X))

T = 5×2 table
    A          B      
    __    ____________

    11    {'1'       }
    22    {'2,3,4'   }
    33    {0×0 double}
    44    {'6,7'     }
    55    {'8'       }

[Erik J]

Works perfectly. Thank you.