Python通过format函数格式化显示值

英文文档：format(value[,format_spec])Convertavaluetoa“formatted”representation,ascontrolledbyformat_spec.Theinterpretationofformat_specwilldependonthetypeofthevalueargument,howeverthereisastandardformattingsyntaxthatisusedbymostbuilt-intypes:FormatSpeci