Use string.join(), which is much more efficent than your approach, which needs to copy the string in every loop. HTH, __Janko -- Institut fuer Meereskunde phone: 49-431-597 3989 Dept. Theoretical Oceanography fax : 49-431-565876 Duesternbrooker Weg 20 email: jhauser at ifm.uni-kiel.de 24105 Kiel, Germany