String input = 'Envelope,Body,describeSObjectResponse,result, custom,customSetting, childRelationships,relationshipName,childSObject'; String[] values = input.split(','); for(integer i=0, max=values.size(); i<max; i++){ values[i] = values[i].trim(); } System.debug('Set<String> xmlTagFilter = new Set<String>{\'' + String.join(values,'\', \'') + '\'};');