2024/8/26
动态创建一个类
类是由TYPE 产生的
dog_class = type("Dog",(object,),{"role":dog})
创建一个Dog类,继承object, 属性 role = dog
def __init__(self,name,age):
self.name = name
self.age = age
dog_class = type("Dog",(object,),{"role":"dog","__init__":__init__})
d = dog_class('zss',25)
isinstance
isinstance(obj,cls)
检查obj是否是类cls的对象
class Foo(object):
pass
obj = Foo()
isinstance(obj,Foo)
issubclass(sub,super)
检查sub类是否是super类的派生类
class Super(object):
pass
class Sub(Super):
pass
issubclass(Sub,Super)
检测 可能发生的错误
try:
'''your code'''
except Exception:
'''上面的程序执行出错后就执行这里的代码'''
else:
'''没发生异常走这里'''
finally:
'''无论是否发生异常,都走这里'''
raise IndexError# 主动触发异常
while True:
num1 = input('num1:')
num2 = input('num2:')
try:
num1 = int(num1)
num2 = int(num2)
except Exception as e:
print('出现异常,信息如下:')
print(e)
Exception 万能异常
打印错误信息,e
强类型错误无法捕捉, 导致 程序崩溃例如: 缩进错误,语法错误
SyntaxError IndentationError
#自定义异常
class MyException(BaseException):#BaseException是所有异常的基类
def __init__(self,msg):
self.message = msg
def __str__(self):
return self.message
try:
raise MyException('错误')
except MyException as e:
print(e)
断言
assert语法用于判断代码是否符合执行预期
assert 1 1 == 3 # 结果为False 报错 AssertionError
