python之字符串格式化

用法:它通过{}和:来代替传统%方式

1.使用位置参数

要点:从以下例子可以看出位置参数不受顺序约束,且可以为{},只要format里有相对应的参数值即可,参数索引从0开,传入位置参数列表可用*列表

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>>> 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.使用关键字参数

要点:关键字参数值要对得上,可用字典当关键字参数传入值,字典前加**即可

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>>> 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.填充与格式化

:[填充字符][对齐方式 <^>][宽度]

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>>> '{0:*>10}'.format(10)  ##右对齐
'********10'
>>> '{0:*<10}'.format(10) ##左对齐
'10********'
>>> '{0:*^10}'.format(10) ##居中对齐
'****10****'

精度与进制

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>>> '{0:.2f}'.format(1/3)
'0.33'
>>> '{0:b}'.format(10) #二进制
'1010'
>>> '{0:o}'.format(10) #八进制
'12'
>>> '{0:x}'.format(10) #16进制
'a'
>>> '{:,}'.format(12369132698) #千分位格式化
'12,369,132,698'

使用索引

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>>> li
['hoho', 18]
>>> 'name is {0[0]} age is {0[1]}'.format(li)
'name is hoho age is 18

This blog is under a CC BY-NC-SA 3.0 Unported License
本文链接:https://blog.suixin.kim/2017/11/29/python-format/