Use the Text to Columns to move each letter found and then stack the columns that were created. That will stack them and you can use the Data column for your axis on you bar chart.
names default to here(1);
dt= New Table( "example",
Add Rows( 3 ),
New Column( "Column 1",
Character,
"Nominal",
Set Values( {"A,B,C,F,G", "B,D", "B,G"} )
)
);
dt << Text To Columns( delimiter( "," ), columns( :column 1 ) );
dtStack = dt << Stack(
columns( :Column 1 1, :Column 1 2, :Column 1 3, :Column 1 4, :Column 1 5 ),
Source Label Column( "Label" ),
Stacked Data Column( "Data" )
);
dtStack << Graph Builder(
Size( 518, 456 ),
Show Control Panel( 0 ),
Variables( Y( :Data ) ),
Elements( Bar( Y, Legend( 3 ), Label( "Label by Value" ) ) )
);
Jim