InStr()

   >>> import string
   >>> teststring = "abcdefgh"
   >>> i = string.index(teststring, 'e')
   >>> print i
   4
   >>> 

>>> aString = 'some simple string'
>>> 'some' in aString
True
>>> 'som' in aString
True
>>> 'simple' in aString
True
>>> 'bla' in aString
False
>>> 'none' in aString
False
>>> 

>>> help(str)
Help on class str in module __builtin__:

class str(basestring)
 |  str(object) -> string
 |  
 |  Return a nice string representation of the object.
 |  If the argument is a string, the return value is the same object.
 |  
 |  Method resolution order:
 |      str
 |      basestring
 |      object
 |  
 |  Methods defined here:
...
 |  
 |  lower(...)
 |      S.lower() -> string
 |      
 |      Return a copy of the string S converted to lowercase.
 |
...
>>>

>>> print chr(65)
A