字符串操作练习：星座、凯撒密码、99乘法表、词频统计预处理

1.实例：输出12个星座符号，以反斜线分隔。

for i in range(12):
    print(chr(9800+i),end='\')
结果：

2.实例：恺撒密码的编码。

mw=input('请输入明文：')
print('密文：',end='')
a=ord('a')
z=ord('z')
for i in mw:
    if a<=ord(i)<z:
        print(chr(a+(ord(i)-a+3)%26),end='')
    else:
        print(i,end='')

结果：

3.输入姓名，格式输出：占4位、居中、不足4字的以空格填充。

name=input('输入姓名：')
print('你的名字：{0:' '^4}'.format(name))

结果：

4.格式化输出：中华人民共和国国内生产总值(GDP)689,136.89亿元(2015年)（千分位、2位小数，浮点数）

print('中华人民共和国国内生产总值（GDP）：{0:,.2f}亿元（{1}年）'.format(689136.89,"2015"))

结果：

 

5.实例：打出99乘法表

for i in range(1,10):
    for j in range(1,10):
        print("{}x{}={}".format(i,j,i*j),end=' ')
        if i==j:
            print("
")
            break
结果：

6.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。

s = '''An unlucky fox fell into a well, It was quite deep, so he could not get out by himself. 
     A goat came. He asked the fox:”what are you doing? The fox said : "There will  be no water, so I jumped down to get some water. Why don’t you jump down, too?" 
     The goat  jumped into the well. 
     But the fox jumped on the goat’s back and out of the well. "Good-bye, friend," said the fox. "Remember next time don’t trust the advice of a man in difficulties." 
     Thank you!'''

print(s)
word = input("请输入查询的单词：")
print("该单词出现的次数为：%d"%str(s).count(word))
for i in s:
    s=str(s).replace(","," ")
    s=str(s).replace("."," ")
    s=str(s).replace("?"," ")
    s=str(s).replace("!"," ")
    s=str(s).lower()
print(s)
结果：

7.用webbrowser，uweb.open_new_tab('url')打开校园新闻列表

import webbrowser as web
web.open_new_tab('http://news.gzcc.cn/html/xiaoyuanxinwen/')

结果：

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