《Python核心编程》第二章习题解答

来源：互联网发布：javascript 取2位小数编辑：程序博客网时间：2024/06/09 21:05

2-4

ch = int(raw_input('Enter some words : '))print ch

2.5

count = 0while count < 11:# use while loop    print count,    count += 1for count in range(0,11):# use for loopprint count,

2.6

number = int(raw_input('Please input a number : '))if number > 0:    print '%d is positive number!' % (number)elif number == 0:    print '%d is zero!' % (number)else:    print '%d is negative number!' % (number)

2.7

ch = raw_input('Enter some words : ')count = 0while (count < len(ch)):print ch[count],count += 1

2.8

"""while loop"""sum_num = 0#aList = [1,2,3,4,5,10]     #initialize listi = 0aList = [1,2,3,4,5]while (i < len(aList)):    aList[i] = int(raw_input('Please input numbers : '))    sum_num += aList[i] # plus    i += 1print sum_num#print sum of list numbers"""for loop"""sum_num = 0aList = [1,2,3,4,5]i = 0for i in range(0,len(aList)):aList[i] = int(raw_input('Please input numbers : '))sum_num += aList[i]i += 1print sum_num

2.9

# while loopcount = 0aList = [1,2,3,4,5]sum_num = 0.0while (count < len(aList)):    num = float(raw_input('Please input numbers : '))    aList[count] = num    sum_num += num    count += 1print sum_num / 5# for loopfor num in range(0,len(aList)):    num = float(raw_input('Please input numbers : '))    aList[count] += num    sum_num += num    count += 1print sum_num / 5

2.10

number = int(raw_input('Please input a number which its range from 1~100:'))Flag = 1while Flag:    if number >= 1 and number <= 100:        print 'Success!'        Flag = 0        break    else:        print 'ERROR!'        number = int(raw_input('Please input again:'))

2.11

def Sum():sum_num = 0aList = [1,2,3,4,5]i = 0for i in range(0,len(aList)):aList[i] = int(raw_input('Please input numbers : '))sum_num += aList[i]i += 1print 'The sum of this five numbers is %d' % (sum_num)def Average():count = 0aList = [1,2,3,4,5]sum_num = 0.0for num in range(0,len(aList)):    num = float(raw_input('Please input numbers : '))    aList[count] += num    sum_num += num    count += 1        print 'The average of this five numbers is %f' % (sum_num / 5)def Menu():print '-----------------------------------------------------'print '(1)Get the sum of five numbers that you input'print '(2)Get the average of five numbers that you input'print '(X)Exit by \'q\''print '-----------------------------------------------------'Flag = 1Menu()choice = raw_input('Please input function you want by 1,2,q: ')while Flag:if choice == '1':Sum()elif choice == '2':Average()elif choice == 'q':Flag = 0breakelse:print 'ERROR!'Menu()choice = raw_input('Please input again:')

2.15

num1 = int(raw_input('Please input number1: '))num2 = int(raw_input('Please input number2: '))num3 = int(raw_input('Please input number3: '))count = 0while count < 6:if num1 > num2:num1,num2 = num2,num1# print '1 and 2 Exchange!'elif num1 > num3:num1,num3 = num3,num1# print '1 and 3 Exchange'elif num2 > num3:num2,num3 = num3,num2# print '2 and 3 Exchange'count += 1print 'The sort form low to top is %d %d %d !' % (num1,num2,num3)

2.16

filename = raw_input('Enter file name: ')fobj = open(filename,'r')for eachLine in fobj:print eachLine,fobj.close()

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