I'm looking into overloading the + operator for a certain string so I was thinking of subclassing the string class then adding the code in the new class. However I wanted to take a look at the standard string class first but I can't seem to find it... stupid eh?
Can anyone point the way? Even online documentation of the source code.
It's documented here. The main implementation is in Objects/stringobject.c. Subclassing str probably isn't what you want, though. I would tend to prefer composition here; have an object with a string field, and special behavior.
You might mean this.
class MyCharacter( object ):
def __init__( self, aString ):
self.value= ord(aString[0])
def __add__( self, other ):
return MyCharacter( chr(self.value + other) )
def __str__( self ):
return chr( self.value )
It works like this.
>>> c= MyCharacter( "ABC" )
>>> str(c+2)
'C'
>>> str(c+3)
'D'
>>> c= c+1
>>> str(c)
'B'
my implementation is similar, though not as neat:
class MyClass:
def __init__(self, name):
self.name = name
def __add__(self, other):
for x in range(1, len(self.name)):
a = list(self.name)[-1 * x]
return self.name[:len(self.name)-x] + chr(ord(a) + other)
>>> CAA = MyClass('CAA')
>>> CAA + 1
'CAB'
>>> CAA + 2
'CAC'
>>> CAA + 15
'CAP'
This appears to be a link that is not currently dead in 2020: https://svn.python.org/projects/python/trunk/Objects/stringobject.c
