1.str（)函数，将数字转换为字符串

2.正向搜索与反向搜索

3，replace()实现字符串的替换，实际上是创建了一个新的zi'fu'chu'a

>>> #从控制台读取字符串
>>> myname=input('请输入名字')
请输入名字llh
>>> myname
'llh'
>>> int('12345')
12345
>>> float('5.20')
5.2
>>> str(12345)
'12345'
>>> str(Float)
Traceback (most recent call last):
  File "<pyshell#130>", line 1, in <module>
    str(Float)
NameError: name 'Float' is not defined
>>> str(False)
'False'
>>> a-'abcdefghijklmnopqrstuvwxyz'
Traceback (most recent call last):
  File "<pyshell#132>", line 1, in <module>
    a-'abcdefghijklmnopqrstuvwxyz'
NameError: name 'a' is not defined
>>> a='abcdefghijklmnopqrstuvwxyz'
>>> a[0]
'a'
>>> a[3]
'd'
>>> a[26]
Traceback (most recent call last):
  File "<pyshell#136>", line 1, in <module>
    a[26]
IndexError: string index out of range
>>> a[25]
'z'
>>> a[-1]
'z'
>>> a[-26]
'a'
>>> a=a.replace("c","高")
>>> a
'ab高defghijklmnopqrstuvwxyz'
>>> b='ddddd'
>>> b=b.replace('d','高’)
        
SyntaxError: EOL while scanning string literal
>>> b.replace('d','s')
'sssss'
>>>