Create watchlist from filter dynamically using today's date

I want to add the results to watchlist with name using today’s date, instead of hard code the watchlist number. I could only achieve the hard-coded watchlist number. Please share.

listnum = 1; 
if ( Status( "stocknum" ) == 0 ) {
    oldlist = CategoryGetSymbols( categoryWatchlist, listnum );
    for ( i = 0; ( sym = StrExtract( oldlist, i ) ) != ""; i++ )    {
        CategoryRemoveSymbol( sym, categoryWatchlist, listnum );
    } 
}
if( LastValue( Filter ) ) 
{ CategoryAddSymbol( "", categoryWatchlist, listnum ); }

Use CategoryFind() function to refer to watch list name and find its corresponding ID.