f前綴用來(lái)格式化字符串,例如

>>> name = 'Fred'
>>> age = 42
>>> f'He said his name is {name} and he is {age} years old.'
He said his name is Fred and he is 42 years old.

可以看出f前綴可以簡(jiǎn)單有效的格式化字符串,比起format()方法具備更好的可讀性

>>> name = 'Fred'
>>> age = 42
>>> 'He said his name is {} and he is {} years old.'.format(name, age)
'He said his name is Fred and he is 42 years old.'

而且加上f前綴后,支持在大括號(hào)內(nèi),運(yùn)行Python表達(dá)式

>>> name = 'Fred'
>>> seven = 7
>>> f'''He said his name is {name.upper()}
...    and he is {6 * seven} years old.'''
'He said his name is FRED\n    and he is 42 years old.'

你還可以用fr前綴來(lái)表示來(lái)表示原生字符串

參考(The new f-strings in Python 3.6)[https://cito.github.io/blog/f-strings/]