一、異常處理

"""
1、什麼是異常
    異常是錯誤發生的訊號，一旦程式出錯就會產生一個異常
    如果該異常沒有被處理，該異常就會被丟擲來，程式的執行隨即終止

    異常是由三部分組成
        1、具體哪一行程式碼丟擲的異常
        2、異常的種類
            NameError:變數名沒有定義過
            IndexError:索引不存在
                l=[11,22]
                l[100]
            KeyError
                d={"k1":11}
                d["k2"]

            AttributeError:物件屬性不存在
                物件.屬性

            ValueError:
                int("asdf")

            TypeError:
                "asdf"+1111

            ZeroDivisionError
                1/0
        3、異常的內容資訊

2、為何要處理異常
    為了增強程式的健壯性

3、如何處理異常
    1、針對語法的錯誤：應該在程式執行前立即改正
    2、針對邏輯錯誤：
        2.1 如果邏輯錯誤發生的條件是可以預知的，應該if判斷解決，預防異常
            age = input('>>: ').strip()
            if age.isdigit():
                age=int(age)
                if age > 18:
                    print('too big')
                elif age < 18:
                    print('too small')
                else:
                    print("got it")
            else:
                print('必須輸入數字')
        2.2 如果邏輯錯誤發生的條件是不可預知的，那麼異常一個會發生，考慮到程式的健壯性
            我們應該處理異常，做好補救措施
            try:
                程式碼塊
            except 異常的型別:
                發生異常後要執行的程式碼

 
"""


# 例1
# try:
#     print("====>111")
#     print("====>222")
#     xxx
#     print("====>333")
# except AttributeError as e:
#     print(e)
#
# print('====>4')

# 例2
# try:
#     print("====>111")
#     print("====>222")
#     xxx
#     print("====>333")
# except NameError as e:
 

#     print(e)
#
# print('====>4')

# # 例3
# try:
#     print("====>111")
#     print("====>222")
#     # xxx
#     # l=[]
#     # l[0]
#     dic={}
#     dic["k1"]
#     print("====>333")
# except (NameError,IndexError) as e:
#     print("=---->",e)
# except KeyError as e:
#     print(e)
 

#
# print('====>4')

# # 例4
# try:
#     print("====>111")
#     print("====>222")
#     xxx=111
#     # l=[]
#     # l[0]
#     dic={}
#     # dic["k1"]
#     print("====>333")
# except (NameError,IndexError) as e:
#     print("=---->",e)
# except KeyError as e:
#     print(e)
# finally:
#     print("一定會執行")
# print('====>4')
# # print(xxx)


# # 例4
# try:
#     print("====>111")
#     print("====>222")
# finally:
#     print("一定會執行")
# print('====>4')
# # print(xxx)

# # 例5
# try:
#     print("====>111")
#     print("====>222")
#     # xxx
#     l=[]
#     # l[0]
#     dic={}
#     dic["k1"]
#     print("====>333")
# except Exception as e:
#     print("萬能異常",e)
# print('====>4')

# 例6
# print('==>11')
# raise NameError("變數名未定義")
# print('==>222')


# class Animal:
#     def speak(self):
#         raise BaseException("小垃圾必須實現speak方法來覆蓋")
#
#     def run(self):
#         raise BaseException("小垃圾必須實現run方法來覆蓋")
#
#
# class Dog(Animal):
#     pass
#
# class Pig(Animal):
#     pass
#
#
# d=Dog()
# p=Pig()
#
# d.speak()
# d.run()

# p.speak()
# d.run()

# 例7
# class Interface(BaseException):
#     def __init__(self, msg, x, y, z):
#         self.msg = msg
#         self.x = x
#         self.y = y
#         self.z = z
#
#     def __str__(self):
#         return "<%s:%s:%s:%s>" % (self.msg,self.x,self.y,self.z)
#
#
# raise Interface("介面異常", 11, 22, 33)

# 例8：

print("====1")
print("====2")
print("====3")
salaries=[1.1,2.2]

# if len(salaries) != 3:
#     raise NameError
assert len(salaries) == 3

print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])
print(salaries[2])