1.

list = [1, 2, 3, 4, 5, 2, 6, 7, 2]
pos = 0
for i in range(list.count(2)):
    if pos == 0:
        pos = list.index(2)
    else:
        pos = list.index(2, pos + 1)
    print 'find pos: ', pos

2.

#递归n的阶乘
def factorial(n):
    if n == 1:
        return 1
    else:
        return n * factorial(n-1)
print factorial(10) 

def factorial(n):
    i = 1
    if n > 1:
        i = n
        n = n * factorial(n-1)
    print "%d! = " %i, n
    return n    
factorial(10)

from functools import reduce
print "10! =", reduce(lambda x, y: x * y, range(1, 11))

3.

#定义一个函数，实现输入n，输出0-n之间的所有素数
def isPrime(n):        
    for i in range(0, n + 1):
        if i == 0:
            print i, 'is not prime'
        elif i == 1:
            print i, 'is not prime'
        else:
            for j in range(2, i):
                if i % j == 0:
                    print i, 'is not prime'
                    break
            else:
                print i, 'is prime'
isPrime(100)  

4.

#判断一个数是否为素数
def isPrime(n):
    if n > 1:
        for i in range(2, n):
            if n % i == 0:
                print n, 'is not prime'
                break
        else:
            print n, 'is prime'
    else:
        print n, 'is not prime'  
isPrime(100) 

5.

#可变参数列表
def test(tep, *args):
    print args
test(1, 2, 3, 4, 5) 

6.

#关键字参数
def parrot(voltage, state='a stiff', action='voom', type='Norwegian Blue'):
    print "-- This parrot wouldn't", action,
    print "if you put", voltage, "volts through it."
    print "-- Lovely plumage, the", type
    print "-- It's", state, "!"
parrot(1000)                                          # 1 positional argument
parrot(voltage=1000)                                  # 1 keyword argument
parrot(voltage=1000000, action='VOOOOOM')             # 2 keyword arguments
parrot(action='VOOOOOM', voltage=1000000)             # 2 keyword arguments
parrot('a million', 'bereft of life', 'jump')         # 3 positional arguments
parrot('a thousand', state='pushing up the daisies')  # 1 positional, 1 keyword  

7.

#默认参数值
def ask_ok(prompt, retries=4, complaint='Yes or no, please!'):
    while True:
        ok = raw_input(prompt)
        if ok in ('y', 'ye', 'yes'):
            return True
        if ok in ('n', 'no', 'nop', 'nope'):
            return False
        retries = retries - 1
        if retries < 0:
            raise IOError('refusenik user')
        print complaint
#ask_ok('Do you really want to quit?')
#ask_ok('OK to overwrite the file?', 2)
ask_ok('OK to overwrite the file?', 2, 'Come on, only yes or no!') 

8.

# write Fibonacci series up to n
def fib(n):    
    """Print a Fibonacci series up to n."""
    a, b = 0, 1
    while a < n:
        print a,
        a, b = b, a+b
# Now call the function we just defined:      
fib(2000)  
fibs = [0, 1]
num = input('How many Fibonacci numbers do you want? ')
for i in range(num - 2):
    fibs.append(fibs[-2] + fibs[-1])
print fibs  

9.

#!/usr/bin/env python
#-*- coding: utf-8 -*-
import sys
count = 0
while True:
    print u"选择你要暂停的行: ",
    print_num = input('')
    while count < 500:
        if print_num <= count:
            if print_num == count:
                print u"你要暂停的行为 ", print_num
                print u"是否要继续(y/n)",
                choice = raw_input('')
                if choice == 'n':
                    sys.exit()
                else:
                    break
            else:
                if print_num <= count:
                    print u"已经过去了"
            break
        else:
            count +=1
            print '现在是第%d行 '  %count 

10.

#!/usr/bin/env python
#-*- coding: utf8 -*-
print_num = input('Which loop do you want it to be printed out?')
count = 0
while count < 10000000:
    if count == print_num:
        print 'There you get the number:', count
        choice = raw_input('Do you want to continue the loop?(y/n)')
        if choice == 'n':
            break
        else:
            while print_num <= count:
                print_num = input('Which loop do you want it to be printed out?')
                if print_num <= count:
                    print u"已经过了"
    else:
        print 'Loop:', count
    count +=1
else:
    print 'Loop:', count

11.

#!-*- coding: utf-8 -*-
#!/usr/bin/env python
import sys
import os
retry_limit = 3
retry_count = 0
account_file = 'account.txt'
lock_file = 'account_lock.txt'
while retry_count < retry_limit:
    username = raw_input('\033|32;1mUsername: \033|0m')
    lock_check = file(lock_file)
    for line in lock_check.readlines():
        line = line.split()
        if username == line[0]:
            sys.exit('\033|31;1mUsername %s is locked!\033|0m')
    password = raw_input('\033|32;1mPassword:\033|0m')
    f = file(account_file, 'rb')
    match_flag = False
    for line in f.readlines():
        user, passwd = line.strip('\n').split()
        if username == user and password == passwd:
            print 'Match!', username
            match_flag  = True
            break
    f.close()
    if match_flag == False:
        print 'User unmatched!'
        retry_count +=1
    else:
        print "Welcom login OldBoy Learning system!"
else:
    print "Your account is locked!"
    f = file(lock_file, 'ab')
    #f.write(username + "\r\n")
    f.write('%s%s' %(username,os.linesep))
    f.close() 

12.

#词频统计
import string

with open('words.txt','r') as text:
    words = [raw_word.strip(string.punctuation).lower() for raw_word in text.read().split()]
    words_index = set(words)
    counts_dict = {index:words.count(index) for index in words_index}
for word in sorted(counts_dict,key=lambda x: counts_dict[x],reverse=True):
    print '{} -- {} times'.format(word,counts_dict[word])

13.

#sorted函数按value值对字典排序
dic = {'a':31, 'bc':5, 'c':3, 'asd':4, '33':56, 'd':0}
print sorted(dic.iteritems(), key=lambda d:d[1], reverse = False)
print sorted(dic.iteritems(), key=lambda d:d[0], reverse = False)
print sorted(dic.items(), key=lambda d:d[1], reverse = False)
print sorted(dic.items(), key=lambda d:d[0], reverse = False)
print sorted(dic, key=lambda d:dic[d] reverse = False)

14.

#字符串的反转
def reverse(s):
    return s[::-1]

s = "hello world"
print reverse(s)

15.

#字符串与日期的转换
import time
import datetime
print time.strftime("%Y-%m-%d %X", time.localtime())
t = time.strptime("2008-08-08", "%Y-%m-%d")
y, m, d = t[0:3]
print datetime.datetime(y, m, d)

16

#正则表达式示例
import re
pattern = re.compile(r"[(]?\d{3}[)-]?\d{8}")
match = pattern.match("(755)12345678")
if match:
    print match.group()