python面试题大全（一）详解编程语言

1 a,b = 0, 1 
2 while b<100: 
3     print (b), 
4     a, b = b, a+b

def choose(bool, a, b): 
    return (bool and [a] or [b])[0]

for x in reversed(sequence): 
    ... # do something with x..

for i in range(len(sequence)-1, -1, -1): 
    x = sequence[i] 
    <do something with x>

 1 函数                      描述 
 2 int(x [,base ])         将x转换为一个整数 
 3 long(x [,base ])        将x转换为一个长整数 
 4 float(x )               将x转换到一个浮点数 
 5 complex(real [,imag ])  创建一个复数 
 6 str(x )                 将对象 x 转换为字符串 
 7 repr(x )                将对象 x 转换为表达式字符串 
 8 eval(str )              用来计算在字符串中的有效Python表达式,并返回一个对象 
 9 tuple(s )               将序列 s 转换为一个元组 
10 list(s )                将序列 s 转换为一个列表 
11 chr(x )                 将一个整数转换为一个字符 
12 unichr(x )              将一个整数转换为Unicode字符 
13 ord(x )                 将一个字符转换为它的整数值 
14 hex(x )                 将一个整数转换为一个十六进制字符串 
15 oct(x )                 将一个整数转换为一个八进制字符串

1 >>> l = tuple(iplist) 
2 >>> print l 
3 ('217.169.209.2:6666', '192.227.139.106:7808', '110.4.12.170:83', '69.197.132.80:7808', '205.164.41.101:3128', '63.141.249.37:8089', '27.34.142.47:9090') 
4 >>> t = list(l) 
5 >>> print t 
6 ['217.169.209.2:6666', '192.227.139.106:7808', '110.4.12.170:83', '69.197.132.80:7808', '205.164.41.101:3128', '63.141.249.37:8089', '27.34.142.47:9090']

1 >>> l = [1,1,2,3,4,5,4] 
2 >>> list(set(l)) 
3 [1, 2, 3, 4, 5] 
4 或者 
5 d = {} 
6 for x in mylist: 
7     d[x] = 1 
8 mylist = list(d.keys())

 1 #使用__metaclass__（元类）的高级python用法   
 2 class Singleton2(type):   
 3     def __init__(cls, name, bases, dict):   
 4         super(Singleton2, cls).__init__(name, bases, dict)   
 5         cls._instance = None   
 6     def __call__(cls, *args, **kw):   
 7         if cls._instance is None:   
 8             cls._instance = super(Singleton2, cls).__call__(*args, **kw)   
 9         return cls._instance   
10   
11 class MyClass3(object):   
12     __metaclass__ = Singleton2   
13   
14 one = MyClass3()   
15 two = MyClass3()   
16   
17 two.a = 3   
18 print one.a   
19 #3   
20 print id(one)   
21 #31495472   
22 print id(two)   
23 #31495472   
24 print one == two   
25 #True   
26 print one is two   
27 #True  

 1 #使用装饰器(decorator),   
 2 #这是一种更pythonic,更elegant的方法,   
 3 #单例类本身根本不知道自己是单例的,因为他本身(自己的代码)并不是单例的   
 4 def singleton(cls, *args, **kw):   
 5     instances = {}   
 6     def _singleton():   
 7         if cls not in instances:   
 8             instances[cls] = cls(*args, **kw)   
 9         return instances[cls]   
10     return _singleton   
11   
12 @singleton   
13 class MyClass4(object):   
14     a = 1   
15     def __init__(self, x=0):   
16         self.x = x   
17   
18 one = MyClass4()   
19 two = MyClass4()   
20   
21 two.a = 3   
22 print one.a   
23 #3   
24 print id(one)   
25 #29660784   
26 print id(two)   
27 #29660784   
28 print one == two   
29 #True   
30 print one is two   
31 #True   
32 one.x = 1   
33 print one.x   
34 #1   
35 print two.x   
36 #1  

 1 #! /usr/bin/env python 
 2 #coding=utf-8 
 3 import sys  
 4 import time  
 5 import poplib  
 6 import smtplib  
 7 #邮件发送函数 
 8 def send_mail():  
 9      try:  
10         handle = smtplib.SMTP('smtp.126.com',25)  
11         handle.login('[email protected]','**********')  
12         msg = 'To: [email protected]/r/nFrom:[email protected]/r/nSubject:hello/r/n' 
13         handle.sendmail('[email protected]','[email protected]',msg)  
14         handle.close()  
15         return 1 
16     except:  
17         return 0 
18 #邮件接收函数 
19 def accpet_mail():  
20     try:  
21         p=poplib.POP3('pop.126.com')  
22         p.user('[email protected]')  
23         p.pass_('**********')  
24         ret = p.stat() #返回一个元组:(邮件数,邮件尺寸)  
25        #p.retr('邮件号码')方法返回一个元组:(状态信息,邮件,邮件尺寸)    
26     except poplib.error_proto,e:  
27         print "Login failed:",e  
28         sys.exit(1) 
29      
30 #运行当前文件时，执行sendmail和accpet_mail函数 
31 if __name__ == "__main__":  
32     send_mail()  
33     accpet_mail()

 1 import os.path 
 2 import xlrd,sys 
 3  
 4 Filename=’/home/tom/Desktop/1234.xls’ 
 5 if not os.path.isfile(Filename): 
 6     raise NameError,”%s is not a valid filename”%Filename 
 7  
 8 bk=xlrd.open_workbook(Filename) 
 9 shxrange=range(bk.nsheets) 
10 print shxrange 
11  
12 for x in shxrange: 
13     p=bk.sheets()[x].name.encode(‘utf-8′) 
14     print p.decode(‘utf-8′)

1 reload(sys) 
2 sys.setdefaultencoding(‘utf8′)

1 b1=[1,2,3] 
2 b2=[2,3,4] 
3 b3 = [val for val in b1 if val in b2] 
4 print b3

1 b1=[1,2,3] 
2 b2=[2,3,4] 
3 b3 = [val for val in b1 if val not in b2] 
4 print b3 

socket = socket.socket( family, type )

socket.bind( address )

socket.listen( backlog )

connection, address = socket.accept()

socket.connect( (host,port) )

 1 #coding:utf-8 
 2  
 3 import socket 
 4 if __name__ == '__main__': 
 5     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
 6     sock.bind(('localhost', 8001)) 
 7     sock.listen(5) 
 8  
 9     while True: 
10         connection,address = sock.accept() 
11         try: 
12             connection.settimeout(5) 
13             buf = connection.recv(1024) 
14             if buf == '1': 
15                 connection.send('welcome to server!') 
16             else: 
17                 connection.send('please go out!') 
18         except socket.timeout: 
19             print 'time out' 
20  
21         connection.close() 

 1 #coding:utf-8 
 2  
 3 import socket 
 4 import time 
 5  
 6 if __name__ == '__main__': 
 7     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
 8     sock.connect(('localhost', 8001)) 
 9     time.sleep(2) 
10     sock.send('1') 
11     print sock.recv(1024) 
12     sock.close() 

 1  try:   
 2        block   
 3     except [exception,[data…]]:   
 4        block   
 5       
 6     try:   
 7     block   
 8     except [exception,[data...]]:   
 9        block   
10     else:   
11        block  

1 raise [exception[,data]]   
2       
3     try:   
4         raise MyError #自己抛出一个异常   
5     except MyError:   
6         print 'a error'   
7       
8     raise ValueError,’invalid argument’  

1     import sys   
2     try:   
3        block   
4     except:   
5        info=sys.exc_info()   
6        print info[0],":",info[1]