maarten van damme: writeln(providor_symbol_map.keys.sort!((x,y)=>providor_symbol_map[x].length>=providor_symbol_map[y].length)); [/code] Try: ((x, y) => providor_symbol_map[x].length > providor_symbol_map[y].length) Bye, bearophile
writeln(providor_symbol_map.keys.sort!((x,y)=>providor_symbol_map[x].length>=providor_symbol_map[y].length)); [/code]