age = input("how old are you? \n")
int(age)
print(type(age))
# <class 'str'>
age = input("how old are you? \n")
age_as_int = int(age)
print(type(age_as_int))
# <class 'int'>
age = input("how old are you? \n")
int(age)
print(type(age))
# <class 'str'>
age = input("how old are you? \n")
age_as_int = int(age)
print(type(age_as_int))
# <class 'int'>
当您使用str()，int()，Float()将一种数据类型转换为另一种数据类型时，您需要将值赋给一个变量，因为您可以看到，它们是函数，它们返回一些东西，如果您不将这些东西放入一个变量中，它就会丢失.
要让您的第一个代码正常工作，它应该是:
age = input("how old are you? \n")
age = int(age)
print(type(age))
或者也许
age = int(input("how old are you? \n"))
print(type(age))