格式化输出

一、字符串的格式化输出

1.标点拼接

1）+

>>> st1 = 'LO'
>>> st2 = 'VE'
>>> st = st1 + st2
>>> st
'LOVE'

2）,

注：用逗号拼接之后变为元组。

>>> st1 = 'LO'
>>> st2 = 'VE'
>>> st = st1,st2
>>> st
('LO', 'VE')

3）不添加任何字符

>>> st = 'LO''VE'
>>> st
'LOVE'
>>> 

2. 在指定位置插入字符

%

字符

插入字符用%s

①插入单个字符

>>> st1 = 'world'
>>> st = 'hello %s'%st1
>>> st
'hello world'

②插入多个字符

>>> st1 = ' '
>>> st2 = 'world'
>>> st3 = '!!'
>>> st = 'hello%s%s%s'%(st1,st2,st3)
>>> st
'hello world!!'

③控制长度

只需在%后边加上参数

>>> st = '123%3s'%123456
>>> st
'123123456'

数字

插入数字用%d

>>> st = '123%d'%1
>>> st
'1231'

浮点数

插入浮点数用%f

>>> st = '123%f'%3.14
>>> st
'1233.140000'

join

''.join(列表名)

举例：

>>> mylist = ['I','LOVE','YOU','!']
>>> st = ''.join(mylist)
>>> st
'ILOVEYOU!'
>>> st = ' '.join(mylist)
>>> st
'I LOVE YOU !'
>>> st = '***'.join(mylist)
>>> st
'I***LOVE***YOU***!'
>>> st = '---'.join(mylist)
>>> st
'I---LOVE---YOU---!'

format

1. 与%类似，占位符用{}，后缀为format（str1,str2）

>>> st = 'name:{} age:{} sex:{}'.format('SuXin','18','man')
>>> st
'name:SuXin age:18 sex:man'
>>> st = 'name:{2} age:{1} sex:{0}'.format('SuXin','18','man')
>>> st
'name:man age:18 sex:SuXin'

2. 指定属性插入，在{}中写入要插入的属性，后缀采用“属性=值”的形式

>>> st = 'name:{name}  age:{age}  sex:{sex}'.format(name='SuXin',age=18,sex='Man')
>>> st
'name:SuXin  age:18  sex:Man'

3. 补位，<字符在左边 >字符在右边 ^字符在中间

>>> '{a:*<30}'.format(a='SuXin')
'SuXin*************************'
>>> '{a:*>30}'.format(a='SuXin')
'*************************SuXin'
>>> '{a:*^30}'.format(a='SuXin')
'************SuXin*************'

4. 传入变量，将该整合的字符串赋值给一个变量，然后变量名加要添加的字符即可实现

>>> st = 'Number: {}'.format
>>> st(1)
'Number: 1'
>>> st('One')
'Number: One'