python核心编程第6章习题答案

3：
（1）：学习一下第3行的用法

num=raw_input("enter all the num and split with space:").split()num=[int(eachStr) for eachStr in num]#学习一下这种用法sortedList=sorted(num)[::-1]print sortedList

结果：

enter all the num and split with space:1 44 23 99 112[112, 99, 44, 23, 1]

（2）：
字典序：字典排列字符串是比较首字符的ASCII码的，如果一样则比较第二个字符，直到有一方胜出，如果长度不一样的话，则字符串较长的那个值大！

num=raw_input("enter all the num and split with space:").split()sortedList=sorted(num)[::-1]print sortedList

结果：

enter all the num and split with space:1 90 104 23 44['90', '44', '23', '104', '1']

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5
（a）：

inStr=raw_input("enter the str:")strlen=len(inStr)if strlen%2==0:    for i in range(strlen/2):        print (inStr[i],inStr[strlen-1-i])else:    for i in range(strlen/2+1):        print (inStr[i],inStr[strlen-1-i])

（c）：

inStr=raw_input("enter the str:")strlen=len(inStr)flag=Truefor i in range(strlen/2):    if inStr[i]!=inStr[strlen-1-i]:        flag=Falseif flag==True:    print "yes"else:    print "no"

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6，
我用了个超蠢的方法，如下：

# -*- coding: utf-8 -*-"""Created on Tue Nov 01 17:19:59 2016@author: yangJirui"""theStr = raw_input("enter  the string:")print repr(theStr)str_len = len(theStr)start = 0end = str_lenfor i in range(str_len - 1):    if theStr[0] != ' ':        break    elif theStr[i] == ' ' and theStr[i+1] != ' ':        start = i + 1        breakfor i in range(1,str_len)[::-1]:    if theStr[-1] != ' ':        break    elif theStr[i] == ' ' and theStr[i - 1] != ' ':        end = i        breakif theStr.count(' ') == str_len:    start = 0    end = 0theStr = theStr[start:end]print repr(theStr)

结果：

enter  the string:   d dd  ddd    ddd      '   d dd  ddd    ddd      ''d dd  ddd    ddd'

博客【1】的方法不错，贴一下：

def del_space(str):    str = list(str)    i = 0    lenth = len(str)    while str[0] == ' ':        str.pop(0)    while str[-1] == ' ':        str.pop()    return ''.join(str)if __name__ == "__main__":    while True:        string = raw_input('Enter a string("q" to quit):')        if string == "q":            break        else:            print del_space(string)

7
修改后为：

inStr=raw_input("enter the str:")num=int(inStr)numList=range(1,num)newList=numList[:]print numListfor i in numList:    if num % i==0:        del newList[newList.index(i)]print newListprint numList

结果：

enter the str:12[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11][5, 7, 8, 9, 10, 11][1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]

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8

def num99Trans(num):    nameList = ['zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten', 'eleven',                 'twelve', 'thirteen']    numList = range(14)    finalName = "erro"    if num <= 13:        # deal special name        finalName = nameList[numList.index(num)]    elif num <= 99:        numTuple = (shiWei, geWei) = divmod(num, 10)        nameList[0] = ''        if shiWei == 1:            if geWei == 5:                finalName = 'fifteen'            else:                finalName = nameList[numList.index(geWei)] + 'teen'        elif shiWei == 2:            finalName = 'twenty ' + nameList[numList.index(geWei)]        elif shiWei == 3:            finalName = 'thirty ' + nameList[numList.index(geWei)]        elif shiWei == 5:            finalName = 'fifty ' + nameList[numList.index(geWei)]        else:            finalName = nameList[numList.index(shiWei)] + 'ty ' + nameList[numList.index(geWei)]    else:        print 'over 100 in num99Trans'    return finalNamedef num1000Trans(num):    nameList=('','one','two','three','four','five','six','seven','eight','nine','ten','eleven',                    'twelve','thirteen')    numList = range(14)    finalName="erro"    if 100<=num<=999:        (baiWei,shiGeWei)=divmod(num,100)        (shiWei,geWei)=divmod(shiGeWei,10)        if shiWei==0:            finalName=nameList[ numList.index(baiWei)]+' hundred and '+nameList[ numList.index(geWei) ]        else:            finalName=nameList[ numList.index(baiWei)]+' hundred '+num99Trans(shiGeWei)    elif num==1000:        finalName='one thusand'    else:        print 'over 1000 in num1000Trans'    return finalNameif __name__=='__main__':    num = int(raw_input("enter the num::"))    if num<100:        print num99Trans(num)    elif num<=1000:        print num1000Trans(num)    else:        print"num is too large or small"

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9

def transM2H(minutes):    (hours,minutes)=divmod(minutes,60)    while minutes>60:        templeHour,mniutes=divmod(mniutes,60)        hours+=templeHour    return (hours,minutes)if __name__=='__main__':    minutes = int(raw_input('enter the minutes::'))    print "hours:%d,minutes:%d" % transM2H(minutes)

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10

def trans(instr):    return instr.swapcase()def myTrans(instr):    instrList=list(instr)    i=0    for data in instrList:        if 'a'<=data<='z':            instrList[i]=data.upper()        elif 'A'<=data<='Z':            instrList[i]=data.lower()        i+=1    return ''.join(instrList)if __name__=='__main__':    instr=raw_input("enter the string::")    print repr(instr)    print repr( myTrans(instr) )   # print repr(trans(instr))

11

# -*- coding: utf-8 -*-def int2ip(num):    binaryNumList=32*[0]    if num==0:        return '0.0.0.0'    i=-1    while num>0:        #短除法求二进制序列        num,yuShu=divmod(num,2)        binaryNumList[i]=yuShu        i-=1    print binaryNumList    iplist=4*[0]    for j in range(4):        for i in range(8):            iplist[j]+=binaryNumList[j*8+i]*pow(2,7-i)    ipstr=str(iplist[0])+'.'+str(iplist[1])+'.'+str(iplist[2])+'.'+str(iplist[3])    return ipstrdef ip2int(ip):    ipList=ip.split('.')    binaryNumList=32*[0]    intData=( int(ipList[0])<<24 )+( int(ipList[1])<<16 )+( int(ipList[2])<<8 )+int(ipList[3])    #注意这里一定要加括号，因为'+'的优先级高于'<<'    return intData    #109.151.53.1<->1838626049if __name__=='__main__':    while True:        print 20*'-'        print '1:translate ip to int num;'        print '2:translate int num to ip;'        print '3:exit'        print 20*'_'        choice=raw_input("please enter the choice")        if choice=='1':            ip=raw_input('enter the ip')            print ip2int(ip)        elif choice=='2':            num=int(raw_input('enter the num::'))            print int2ip(num)        else:            break

12

# -*- coding: utf-8 -*-def findchr(string,chr):    '''    在字符串string中寻找第一次出现的chr的索引并返回，若没有返回-1    '''    i=0    for eachChr in string:        if eachChr==chr:            return i        i+=1    return -1def rfindchr(string,chr):    '''    从string的右边开始查找第一次出现的chr的索引并返回，若没有则返回-1    '''    string=string[::-1]    i=findchr(string,chr)    if i==-1:        return -1    return -i-1+len(string)    #-1-i是其负数的索引，把其变成正数的索引故要加len(string)def substr(string,origchar,newchar):    '''    在字符串string中找到所有的origchr并全部替换成newchr,返回修改后的字符串    '''    string=list(string)    #将其变换成列表是为了可以直接对list进行操作而不用每修改一次就要产生一次新的字符串对象，可以提高效率    i=0    for eachchr in string:        if eachchr==origchar:            string[i]=newchar        i+=1    return ''.join(string)if __name__=='__main__':    while True:        print 20 * '_'        print "1:find index of char in string"        print "2:find index of char in string but start with right"        print "3:replace origchar in string with newchar"        print "4:exit"        print 20 * '_'        choice = raw_input("enter your choice::")        if choice=='1':            inStr=raw_input("enter the string and char(split with ',')::")            string,chr=inStr.split(',')            print findchr(string,chr)        elif choice=='2':            inStr = raw_input("enter the string and char(split with ',')::")            string, chr = inStr.split(',')            print rfindchr(string, chr)        elif choice=='3':            inStr = raw_input("enter the string ,origchar and newchar(split with ',')::")            string, origchar, newchar = inStr.split(',')            print substr(string,origchar,newchar)        else:            break

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13

# -*- coding: utf-8 -*-def atoc(string):    '''从右边开始查找实部与虚部分割的符号会比较方便，这样可以避免实部是负数    从而导致查找分割符号错误的情况'''    string_len=len(string)-1    index=0    for i in range(string_len,0,-1):        if ( string[i] in ('+','-') ) and string[i-1]!='e':            #防止从右边开始第一个符号是e指数里面的            index=i    real=float(string[0:index])    imag=float(string[index+1:-1])    return complex(real,imag)if __name__=='__main__':    string=raw_input('enter the string\n')    print atoc(string)

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14
我的比较多的if

# -*- coding: utf-8 -*-import randomwhile True:    print 20*'-'    print '0:stone'    print '1:cloth'    print '2:scissor'    print '3:exit'    print 20*'-'    user=int( raw_input('enter your choice::') )    winner='no body'    choice=['stone','cloth','scissor']    if user!=3:        computer=random.randrange(0,3)        print "your\'s is:",choice[user]        print "computer\'s is :",choice[computer]        if (user,computer) in((0,2),(2,0)):            if user>computer:                winner="computer"            else:                winner='user'        elif computer==user:            winner="every body"        elif computer>user:            winner="computer"        else :            winner='user'        print "winner is::",winner    else:        breakprint 'Rochambeau over'

博客【1】if比较少：

from random import choicedef Rochambeau(human_input,PC_input):    if PRS_dict[human_input] == PRS_dict[PC_input]:        return 'It is a tie.'    elif PRS_dict[human_input] - PRS_dict[PC_input] == 1\    or PRS_dict[human_input] - PRS_dict[PC_input] == -2:        return 'You win!'    else:        return 'PC win!'RPS_list = ['R','S','P']    PRS_dict = {'R':1,'S':0,'P':-1} if __name__ == "__main__":    while True:        human_input = (raw_input("Enter 'R' for 'Rock'\,'S' for 'Scissors' and 'P' for 'Paper'(q to quit):")).upper()        if human_input == 'q':            break        else:            PC_input = choice(RPS_list)            print "PC's choice is %s." % PC_input            print Rochambeau(human_input,PC_input)

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19

# -*- coding: utf-8 -*-import randomdef out(list,geShi,num):    length=len(list)    (num_eachline,yuShu)=divmod(length,num)    num_lastline=num_eachline+yuShu    if geShi=='hang':        for i in range(num-1):            print list[0:num_eachline]            del list[0:num_eachline]        print list    elif geShi=='lie':        newList=list[0:num]#只是让newList和list类型一致，不是让newList取list的值        for i in range(num_eachline):            for j in range(num):                newList[j]=list[j*num_eachline+i]            print newList        print [-1,-1, list[-1] ]if __name__=='__main__':    list=[random.randint(1,10) for i in range(100)]    out(list ,'lie',3)    out(list,'hang',3)

贴个结果:
-1代表空格

[2, 8, 10][10, 7, 2][6, 7, 1][7, 1, 2][5, 4, 5][9, 9, 5][9, 7, 8][7, 9, 5][1, 9, 2][10, 1, 5][9, 2, 9][7, 10, 3][2, 1, 3][1, 7, 5][4, 10, 3][10, 5, 9][2, 8, 9][8, 8, 7][10, 8, 7][3, 5, 8][4, 8, 1][3, 1, 3][4, 9, 9][4, 7, 1][9, 2, 4][4, 7, 9][3, 4, 2][3, 8, 4][9, 7, 4][7, 2, 9][3, 10, 2][3, 10, 6][10, 8, 2][-1, -1, 4][2, 10, 6, 7, 5, 9, 9, 7, 1, 10, 9, 7, 2, 1, 4, 10, 2, 8, 10, 3, 4, 3, 4, 4, 9, 4, 3, 3, 9, 7, 3, 3, 10][8, 7, 7, 1, 4, 9, 7, 9, 9, 1, 2, 10, 1, 7, 10, 5, 8, 8, 8, 5, 8, 1, 9, 7, 2, 7, 4, 8, 7, 2, 10, 10, 8][10, 2, 1, 2, 5, 5, 8, 5, 2, 5, 9, 3, 3, 5, 3, 9, 9, 7, 7, 8, 1, 3, 9, 1, 4, 9, 2, 4, 4, 9, 2, 6, 2, 4]

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参考博客：
【1】https://my.oschina.net/linglingqixianke/blog/685275