字符串操作练习：星座、凯撒密码、99乘法表、词频统计预处理

输出12个星座符号，以反斜线分隔。

for i in range(12):
    print(chr(9800+i),end="/")

恺撒密码的编码

sr1="abcdefghijklmnopqrstuvwxyz"
sr2=sr1.upper()
sr=sr1+sr1+sr2+sr2
st=input("please input:")
sR=""
for j in st:
    if j==" ":
        sR = sR +" "
        continue
    i=sr.find(j)
    if(i>-1):
        sR=sR+sr[i-3]
print(sR)

输入姓名，输出占4位、居中、不足4字的以空格填充。

name=input("please input:")
print(name.center(4,' '))

中华人民共和国国内生产总值(GDP)
689,136.89亿元(2015年)

print("中华人民共和国国内生产总值(GDP){:,.2f}亿元(2015年)".format(689136.89))

实例：打出99乘法表

for x in range(1,10):
    for y in range(1,x+1):
        print("{}*{}={}".format(y,x,x*y),end=' ')
    print()

实例: 下载一首英文的歌词或文章，统计单词出现的次数，将所有,.？！替换为空格，将所有大写转换为小写。

sr='''Just one last dance ,oh baby just one last dance!
We meet in the night in the Spanish café,
I look in your eyes just don't know what to say,
It feels like I'm drowning in salty water,A few hours left 'til the sun's gonna rise,
tomorrow will come an it's time to realize.our love has finished forever,
how I wish to come with you!how I wish we make it through!
Just one last dance!before we say goodbye,
when we sway and turn round and round and round,
it's like the first time,Just one more chance,
hold me tight and keep me warm.cause the night is getting cold.
and I don't know where I belong,Just one last dance! '''

print("dance出现次数:",sr.count('dance'))
for i in sr:
    sr=sr.replace(',',' ')
    sr=sr.replace('!',' ')
    sr=sr.replace('?',' ')
print(sr)
for i in sr:
    sr=sr.lower()
print(sr)

sr='''Just one last dance ,oh baby just one last dance!
We meet in the night in the Spanish café,
I look in your eyes just don't know what to say,
It feels like I'm drowning in salty water,A few hours left 'til the sun's gonna rise,
tomorrow will come an it's time to realize.our love has finished forever,
how I wish to come with you!how I wish we make it through!
Just one last dance!before we say goodbye,
when we sway and turn round and round and round,
it's like the first time,Just one more chance,
hold me tight and keep me warm.cause the night is getting cold.
and I don't know where I belong,Just one last dance! '''

print("dance出现次数:",sr.count('dance'))
for i in sr:
    sr=sr.replace(',',' ')
    sr=sr.replace('!',' ')
    sr=sr.replace('?',' ')
print(sr)
for i in sr:
    sr=sr.lower()
print(sr)

webbrowser打开校园新闻列表

import webbrowser as web
i=input("please input number:")
web.open_new_tab('http://news.gzcc.cn/html/xiaoyuanxinwen/'+str(i)+'.html')