模块异常谈python

#!/usr/bin/env python# -*- coding: utf-8 -*-"""__title__ = ‘‘__author__ = ‘cuitbnc‘__mtime__ = ‘2016/10/4‘# 欢迎进入我的主页：http://www.cnblogs.com/baiboy/."""‘‘‘默认函数值：最常用的一种形式是为一个或多个参数指定默认值username：必选参数，用户名password：必选参数，密码limits:可选参数，登陆权限限制complaint：可选参数，登陆错误，剩余次数提示urs=[] ：字典参数‘‘‘def login(username,password, limits=3, complaint=‘you have login times:【‘,urs=[]):    countlimits = limits; #统计自定义限制次数    while True:        usrname= input(username)        usrpwd=input(password)        urs.append("you input data:["+usrname+"-"+usrpwd+"]")    # 记录用户每次登录的信息        print(urs)        if usrname in (‘admin‘, ‘ad‘, ‘bnc‘) and usrpwd in (‘pass‘, ‘pwd‘, ‘password‘, ‘bnc‘):            print(‘Congratulations,Welcome 【‘+usrname+‘】to the login page.‘)            return        else:            print(‘Sorry,【‘+usrname+‘】:you username or password error.‘)            limits = limits - 1        if limits == 0:            print(‘More ‘+str(countlimits)+‘ times,Your account is locked!‘)            return        print(complaint+str(limits)+"】times")

# 只给出必要的参数:login(‘UserName:\t‘,‘PassWord:\t‘)

# 给出一个可选的参数login(‘UserName:\t‘,‘PassWord:\t‘,2)

# 或者给出所有的参数login(‘UserName:\t‘,‘PassWord:\t‘, 2, ‘Remember you enter the correct user name and password,you have login times:‘)

#!/usr/bin/env python# -*- coding: utf-8 -*-"""__title__ = ‘‘__author__ = ‘cuitbnc‘__mtime__ = ‘2016/10/9‘# 欢迎进入我的主页：http://www.cnblogs.com/baiboy/."""import  LoginDomeLoginDome.login(‘UserName:\t\n‘,‘PassWord:\t\n‘)

>>> import sys>>> sys.path[‘‘, ‘E:\\Python\\Lib\\idlelib‘, ‘E:\\Python\\python35.zip‘, ‘E:\\Python\\DLLs‘, ‘E:\\Python\\lib‘, ‘E:\\Python‘, ‘E:\\Python\\lib\\site-packages‘]>>> sys.version‘3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:01:18) [MSC v.1900 32 bit (Intel)]‘

[‘__builtins__‘, ‘__cached__‘, ‘__doc__‘, ‘__file__‘, ‘__loader__‘, ‘__name__‘, ‘__package__‘, ‘__spec__‘, ‘login‘]

[‘__displayhook__‘, ‘__doc__‘, ‘__excepthook__‘, ‘__interactivehook__‘, ‘__loader__‘, ‘__name__‘, ‘__package__‘, ‘__spec__‘, ‘__stderr__‘, ‘__stdin__‘, ‘__stdout__‘, ‘_clear_type_cache‘, ‘_current_frames‘, ‘_debugmallocstats‘, ‘_getframe‘, ‘_home‘, ‘_mercurial‘, ‘_xoptions‘, ‘api_version‘, ‘argv‘, ‘base_exec_prefix‘, ‘base_prefix‘, ‘builtin_module_names‘, ‘byteorder‘, ‘call_tracing‘, ‘callstats‘, ‘copyright‘, ‘displayhook‘, ‘dllhandle‘, ‘dont_write_bytecode‘, ‘exc_info‘, ‘excepthook‘, ‘exec_prefix‘, ‘executable‘, ‘exit‘, ‘flags‘, ‘float_info‘, ‘float_repr_style‘, ‘get_coroutine_wrapper‘, ‘getallocatedblocks‘, ‘getcheckinterval‘, ‘getdefaultencoding‘, ‘getfilesystemencoding‘, ‘getprofile‘, ‘getrecursionlimit‘, ‘getrefcount‘, ‘getsizeof‘, ‘getswitchinterval‘, ‘gettrace‘, ‘getwindowsversion‘, ‘hash_info‘, ‘hexversion‘, ‘implementation‘, ‘int_info‘, ‘intern‘, ‘is_finalizing‘, ‘maxsize‘, ‘maxunicode‘, ‘meta_path‘, ‘modules‘, ‘path‘, ‘path_hooks‘, ‘path_importer_cache‘, ‘platform‘, ‘prefix‘, ‘set_coroutine_wrapper‘, ‘setcheckinterval‘, ‘setprofile‘, ‘setrecursionlimit‘, ‘setswitchinterval‘, ‘settrace‘, ‘stderr‘, ‘stdin‘, ‘stdout‘, ‘thread_info‘, ‘version‘, ‘version_info‘, ‘warnoptions‘, ‘winver‘]

[‘__displayhook__‘, ‘__doc__‘, ‘__excepthook__‘, ‘__interactivehook__‘, ‘__loader__‘, ‘__name__‘, ‘__package__‘, ‘__spec__‘, ‘__stderr__‘, ‘__stdin__‘, ‘__stdout__‘, ‘_clear_type_cache‘, ‘_current_frames‘, ‘_debugmallocstats‘, ‘_getframe‘, ‘_home‘, ‘_mercurial‘, ‘_xoptions‘, ‘api_version‘, ‘argv‘, ‘base_exec_prefix‘, ‘base_prefix‘, ‘builtin_module_names‘, ‘byteorder‘, ‘call_tracing‘, ‘callstats‘, ‘copyright‘, ‘displayhook‘, ‘dllhandle‘, ‘dont_write_bytecode‘, ‘exc_info‘, ‘excepthook‘, ‘exec_prefix‘, ‘executable‘, ‘exit‘, ‘flags‘, ‘float_info‘, ‘float_repr_style‘, ‘get_coroutine_wrapper‘, ‘getallocatedblocks‘, ‘getcheckinterval‘, ‘getdefaultencoding‘, ‘getfilesystemencoding‘, ‘getprofile‘, ‘getrecursionlimit‘, ‘getrefcount‘, ‘getsizeof‘, ‘getswitchinterval‘, ‘gettrace‘, ‘getwindowsversion‘, ‘hash_info‘, ‘hexversion‘, ‘implementation‘, ‘int_info‘, ‘intern‘, ‘is_finalizing‘, ‘maxsize‘, ‘maxunicode‘, ‘meta_path‘, ‘modules‘, ‘path‘, ‘path_hooks‘, ‘path_importer_cache‘, ‘platform‘, ‘prefix‘, ‘set_coroutine_wrapper‘, ‘setcheckinterval‘, ‘setprofile‘, ‘setrecursionlimit‘, ‘setswitchinterval‘, ‘settrace‘, ‘stderr‘, ‘stdin‘, ‘stdout‘, ‘thread_info‘, ‘version‘, ‘version_info‘, ‘warnoptions‘, ‘winver‘]

sound/                          Top-level package      __init__.py               Initialize the sound package      formats/                  Subpackage for file format conversions              __init__.py              wavread.py              wavwrite.py              aiffread.py              aiffwrite.py              auread.py              auwrite.py              ...      effects/                  Subpackage for sound effects              __init__.py              echo.py              surround.py              reverse.py              ...      filters/                  Subpackage for filters              __init__.py              equalizer.py              vocoder.py              karaoke.py

>>> while True:	try:		x = int(input("Please enter a number: "))		break	except ValueError:		print(‘oh,That was no valid number. Try again...‘)Please enter a number: rttroh,That was no valid number. Try again...Please enter a number:

import systry:    f = open(‘myfile.txt‘)    s = f.readline()    i = int(s.strip())except OSError as err:    print("OS error: {0}".format(err))except ValueError:    print("Could not convert data to an integer.")except:    print("Unexpected error:", sys.exc_info()[0])    raise

for arg in sys.argv[1:]:    try:        f = open(arg, ‘r‘)    except IOError:        print(‘cannot open‘, arg)    else:        print(arg, ‘has‘, len(f.readlines()), ‘lines‘)        f.close()

>>> def this_fails():...     x = 1/0>>> try:...     this_fails()... except ZeroDivisionError as err:...     print(‘Handling run-time error:‘, err)Handling run-time error: int division or modulo by zero

>>> try:	raise NameError(‘There name error‘)except NameError:	print(‘An exception flew by!‘)	raiseAn exception flew by!Traceback (most recent call last):  File "<pyshell#196>", line 2, in <module>    raise NameError(‘There name error‘)NameError: There name error

读取文件：for line in open("myfile.txt"):    print(line)如上文件读取没有关闭，则可以采用之前文章介绍的预处理with解决：with open("myfile.txt") as f:    for line in f:        print(line)