在学Python,在看《Python核心编程》的pdf，做了Chap2的题目，答案为DIY

# Filename: 2-11.py

# Author: ChrisZZ

mylist = [1, 2, 3, 4, 6]

sum = 0

for i in mylist:

    sum = sum + i

average = sum * 1.0 / len(mylist)

while True:

    print 'Here we have a list:', mylist

    option = raw_input('Whatyou gonna know(sum/average/exit)?')

    if option == 'sum':

        print 'the sum of the list is', sum

    elif option == 'average':

        print 'the average of the list is', average

    elif option == 'exit':

        print 'Bye'

        break

    else:

        print 'Wrong option.Repeat.'

# Filename: 2-5.py

# Author: ChrisZZ

i = 0

while i <= 10:

    print i

    i = i + 1

for j in range(11):

    print j

# Filename: 2-15.py

# Author: ChrisZZ

print 'Please input 3 number.'

print 'I will sort them without using sort algo'

a = float(raw_input('the first number'))

b = float(raw_input('the second number'))

c = float(raw_input('the third number'))

res1 = (a - b) * (a - c)

mylist = []

if res1 < 0:  # a is the middle

    if b > c:

        mylist = [b, a, c]

    else:

        mylist = [c, a, b]

else:

    if a > b and b > c:

        mylist = [a, b, c]

    elif a > c and c > b:

        mylist = [a, c, b]

    elif a < b and b < c:

        mylist = [c, b, a]

    elif a < c and c < b:

        mylist = [b, c, a]

print mylist

# Filename: 2-10.py

# Author: ChrisZZ

while True:

    num = float(raw_input('Enter a number in range(1,100):'))

    if num > 100 or num < 0:

        print 'not a good number. repeat.'

    else:

        print 'nice number.bye'

        break

# Filename: 2-8.py

# Author: ChrisZZ

mylist = [1, 2, 3, 4, 5]

sumW = 0

i = 0

while i < len(mylist):

    sumW = sumW + mylist[i]

    i = i + 1

print sumW

sumF = 0

for i in mylist:

    sumF = sumF + i

print sumF

# Filename: 2-7.py

# Author: ChrisZZ

s = raw_input('Enter a string:')

print 'while loop:'

i = len(s)

while i > 0:

    print s[-i]

    i = i - 1

print 'for loop:'

for ch in s:

    print ch

# Filename: 2-6.py

# Author: ChrisZZ

num = float(raw_input('Enter a number:'))

if num < .0:

    print 'Negative number'

elif num > .0:

    print 'Positive number'

else:

    print 'Zero'

　　PS：这些题目都是分开写的py脚本，自己写了另一个脚本把他们重定向到了一个叫做result.txt的文件中，习题在~/workspace/python/xiti/路径，处理的脚本在~/workspace/python/，具体如下：

# Filename: process.py

# Author: ChrisZZ

import os

prefix = "/home/chris/workspace/python/xiti/"

filenames = os.listdir(prefix)

out = open('result.txt', 'w')

for k, v in enumerate(filenames):

    f = open(prefix + v, 'r')

    out.write('# Filename: %s\n' % v)

    out.write('# Author: ChrisZZ\n')

    for eachLine in f:

        out.write(eachLine)

    f.close()

    out.write('\n')

out.close()