python 笔记

1.python类中不支持函数重载

2.子类总是覆盖父类的方法，甚者参数列表不同也能覆盖

3.捕捉文件IO异常

try:

fsock = open("/notthere")

except IOError:

print "The file does not exist,exiting gracefully"

print "The line will always print"

4.常见异常

#no dictionray key:    KeyError

#no list value:             ValueError

#no function:              AttributeError

#no variable:             NameError

#no tran data type:  TypeError 

#no module:             ImportError

5.尝试某种操作，操作某个变量，方法，或导入模块

try:

print tanxiaohai

except NameError:

print "the value does not exist"

else:

print "the value exist"

print "always printf"