python中def函數右側有個->的含義

在有->的情況下:

def f(ham: str, eggs: str = 'eggs') -> str:
    print("Annotations:", f.__annotations__)
    print("Arguments:", ham, eggs)
    return ham + ' and ' + eggs


f('spam')

運行結果是:

# Annotations: {'ham': <class 'str'>, 'eggs': <class 'str'>, 'return': <class 'str'>}
# Arguments: spam eggs
 

def f(ham: str, eggs: str = 'eggs'):
    print("Annotations:", f.__annotations__)
    print("Arguments:", ham, eggs)
    return ham + ' and ' + eggs
f('spam')
 

運行結果是:

Annotations: {'ham': <class 'str'>, 'eggs': <class 'str'>}
Arguments: spam eggs

總結:

其實沒啥用，就是註釋的作用，挺花哨的功能．