python核心编程 第二章练习

#encoding=utf-8
from __future__ import division  #除法总是会返回真实的商
from __future__ import unicode_literals #运行时中文编码正确
#练习1 
string = 'hello,world'
intA = 5
print 'string is %s,intA is %d' % (string,intA)

#练习2
print 1 + 2 * 4

#练习3
a = 9
b = 3
print a+b,a-b,a*b, a/b,a%b,a**b

#练习4
print 'please emter string:'
c = raw_input()
print  c
intB = int(raw_input())
print 'intB is %d' % intB

#练习5
i = 0
while i < 11:
    print i
    i += 1  #python 没有++

for j in range(11):
    print j

#练习6   有问题   a = 输入的数据，后续程序并不是
#a = 3
a = raw_input()
print a

if a > 0:
    print 'a > 0'
elif a == 0 :
    print 'a == 0'
else :
    print 'a < 0'

#问题7  
string = raw_input()
strlen = len(string)
i = 0
while i < strlen:
    print string[i]
    i += 1
#for 接受可迭代对象（例如序列或迭代器）作为其参数，
#每次迭代其中一个元素。与传统计数器循环不太一样
for j in string:
    print j

#问题8
aList = [1, 2, 3, 4, 5]    #列表[]
sum = 0
i = 0
while i < len(aList):
    sum += aList[i]
    i += 1
print 'sum while is : %d' % sum
for j in aList:
    sum += j
print 'sum for is : %d' % sum

aTuple = (1, 2, 3, 4, 5)    #元组()
sum = 0
i = 0
while i < len(aTuple):
    sum += aTuple[i]
    i += 1
print 'sum while is : %d' % sum
for j in aTuple:
    sum += j
print 'sum for is : %d' % sum

sum = 0
j = 0
while j < 5:
    i = int(raw_input())
    sum += i
    j += 1
print sum

#问题9
aList = [1, 2, 3, 4]    #列表[]
sum = 0
i = 0
while i < len(aList):
    sum += aList[i]
    i += 1
float(sum)
float(len(aList))

print sum
print float(10 / 4)
print 'average is %f' % (sum/(len(aList)))

问题10
python 逻辑and or not
a = int(raw_input())
while a > 100 or  a < 1:
    print 'input error,again:'
    a = int(raw_input())
print 'sucess %d' % a

#问题11
print '--------------菜单项------------'
print '(1)取五个数的和'
print '(2) 取五个数的差'
print '(X)退出'
select = raw_input()

while select != 'x':
    select = int(select)
    if select == 1:
        print '求和'
        sum = 0
        j = 0
        while j < 5:
            i = int(raw_input())
            sum += i
            j += 1
        print sum
    elif select == 2 :
        print '求均值'
        sum = 0
        j = 0
        while j < 5:
            i = int(raw_input())
            sum += i
            j += 1
        print float(sum/5)
    else :
        print '选择错误'
    print '--------------再次进入菜单项------------'
    print '(1)取五个数的和'
    print '(2) 取五个数的差'
    print '(X)退出'
    select = raw_input()

#问题15
# print 'please enter three numbers'
# a = int(raw_input())
# b = int(raw_input())
# c = int(raw_input())
# if a > b:
#     temp = a
#     a = b
#     b = temp
# if b > c:
#     temp = b
#     b = c
#     c = temp
# if a > b:
#     temp = a
#     a = b
#     b = temp
# print '%d < %d < %d' %(a,b,c)

#问题16
filename = raw_input('enter file name:')
fobj = open(filename,'r')
for x in fobj:
    print x;
fobj.close()