python 异常处理

常见异常

NameError
TypeError
SyntaxError
KeyError
IndexError

# 常见异常
# NameError
#print(1+'a')  #TypeError: unsupported operand type(s) for +: 'int' and 'str'
#print(1+)  # SyntaxError: invalid syntax

d={'x':1}
#print(d['c'])  #KeyError: 'c'
l=[1,2]
#print(l[3])  #IndexError: list index out of range

异常万能捕获 Exception

# 异常万能捕获  Exception
try:
    d = {'x': 1}
    l=[1,2]
except NameError as e:
    print(e)
except Exception as e:
    print(e)
finally:
    print()

自定义异常 raise

# 自定义异常
l=[1,2]
if len(l) != 2:
    raise TypeError('列表长度必须为5')

断言 assert

# 断言
l=[1,2]
assert  len(l) == 2

参考

Python3 错误和异常