用法：
它通過{}和:來代替傳統%方式
1、使用位置參數
要點：從以下例子可以看出位置參數不受順序約束，且可以爲{},只要format裏有相對應的參數值即可,參數索引從0開，傳入位置參數列表可用*列表
>>> li = ['hoho',18]
>>> 'my name is {} ,age {}'.format('hoho',18)
'my name is hoho ,age 18'
>>> 'my name is {1} ,age {0}'.format(10,'hoho')
'my name is hoho ,age 10'
>>> 'my name is {1} ,age {0} {1}'.format(10,'hoho')
'my name is hoho ,age 10 hoho'
>>> 'my name is {} ,age {}'.format(*li)
'my name is hoho ,age 18'
2、使用關鍵字參數
要點：關鍵字參數值要對得上，可用字典當關鍵字參數傳入值，字典前加**即可
>>> hash = {'name':'hoho','age':18}
>>> 'my name is {name},age is {age}'.format(name='hoho',age=19)
'my name is hoho,age is 19'
>>> 'my name is {name},age is {age}'.format(**hash)
'my name is hoho,age is 18'
3、填充與格式化
:[填充字符][對齊方式 <^>][寬度]
>>> '{0:*>10}'.format(10) ##右對齊
'********10'
>>> '{0:*<10}'.format(10) ##左對齊
'10********'
>>> '{0:*^10}'.format(10) ##居中對齊
'****10****'
4、精度與進制
>>> '{0:.2f}'.format(1/3)
'0.33'
>>> '{0:b}'.format(10) #二進制'1010'
>>> '{0:o}'.format(10) #八進制'12'
>>> '{0:x}'.format(10) #16進制'a'
>>> '{:,}'.format(12369132698) #千分位格式化'12,369,132,698'
5、使用索引
>>> li
['hoho', 18]
>>> 'name is {0[0]} age is {0[1]}'.format(li)
'name is hoho age is 18