python2.x捕獲異常語法:
try:
...some functions...
except Exception, e:
print(e)
python3.x捕獲異常語法:
try:
...some functions...
except Exception as e:
print(e)
注意這里 Exception, e 變成了 Exception as e
python常見的異常類型
1. NameError:嘗試訪問一個未申明的變量
>>> v
NameError: name 'v' is not defined
2. ZeroDivisionError:除數(shù)為0
>>> v = 1/0
ZeroDivisionError: int division or modulo by zero
3. SyntaxError:語法錯誤
int int
SyntaxError: invalid syntax (<pyshell#14>, line 1)
4. IndexError:索引超出范圍
List = [2]
>>> List[3]
Traceback (most recent call last):
File "<pyshell#18>", line 1, in <module>
List[3]
IndexError: list index out of range
5. KeyError:字典關鍵字不存在
Dic = {'1':'yes', '2':'no'}
>>> Dic['3']
Traceback (most recent call last):
File "<pyshell#20>", line 1, in <module>
Dic['3']
KeyError: '3'
6. IOError:輸入輸出錯誤
>>> f = open('abc')
IOError: [Errno 2] No such file or directory: 'abc'
7. AttributeError:訪問未知對象屬性
>>> class Worker:
def Work():
print("I am working")
>>> w = Worker()
>>> w.a
Traceback (most recent call last):
File "<pyshell#51>", line 1, in <module>
w.a
AttributeError: 'Worker' object has no attribute 'a'
8.ValueError:數(shù)值錯誤
>>> int('d')
Traceback (most recent call last):
File "<pyshell#54>", line 1, in <module>
int('d')
ValueError: invalid literal for int() with base 10: 'd'
9. TypeError:類型錯誤
>>> iStr = '22'
>>> iVal = 22
>>> obj = iStr + iVal;
Traceback (most recent call last):
File "<pyshell#68>", line 1, in <module>
obj = iStr + iVal;
TypeError: Can't convert 'int' object to str implicitly
10. AssertionError:斷言錯誤
>>> assert 1 != 1
Traceback (most recent call last):
File "<pyshell#70>", line 1, in <module>
assert 1 != 1
AssertionError
11.MemoryError:內(nèi)存耗盡異常
12. NotImplementedError:方法沒實現(xiàn)引起的異常
class Base(object):
def __init__(self):
pass
def action(self):
#拋出異常,說明該接口方法未實現(xiàn)
raise NotImplementedError
13. LookupError:鍵、值不存在引發(fā)的異常
LookupError異常是IndexError、KeyError的基類, 如果你不確定數(shù)據(jù)類型是字典還是列表時,可以用LookupError捕獲此異常
14. StandardError 標準異常
除StopIteration, GeneratorExit, KeyboardInterrupt 和SystemExit外,其他異常都是StandarError的子類。
錯誤檢測與異常處理區(qū)別在于:錯誤檢測是在正常的程序流中,處理不可預見問題的代碼,例如一個調(diào)用操作未能成功結(jié)束。
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