[amibroker] How to Skip Empty Symbols when looping through wishlist

[Paolo Cavatore]

Does anyone know how to skip empty symbols when looping through a 
list of them?

The code below shows that IsNull function doesn't return TRUE for 
empty symbols.

Thanks,

paolo

// EmptySymbols finder
// retrive comma-separated list of symbols
// from Group 0
list = CategoryGetSymbols(categoryGroup, 0); 

Count = 0;

   for( i = 0; ( sym = StrExtract( list, i ) ) != ""; i++ ) 
   { 
        SetForeign(sym);      
        myforeign = C;
        RestorePriceArrays();
        
        //if the symbol is empty Count is not increased
        IIf(IsNull(myforeign), Count, Count++);
        _TRACE("symbol " + sym);
        _TRACE("Count " + Count);
        _TRACE("IsNull " + IsNull(myforeign));

    }