On 07/09/2013 03:01 PM, Russel Walker wrote:
This is a simplified example of what I want to do:
# THIS DOESN'T WORK
from random import choice
class Expr(object):
"""
Expr(expr, op, val) -> an expression object.
"""
def __init__(self, expr, op='', val=''):
self.expr = expr # can be another instance of Expression.
self.op = op
self.val = val
def __str__(self):
return ("%s %s %s" % (self.expr, self.op, self.val)).strip()
def expand(self):
self = Expr(self, choice('+-*/'), choice('12345'))
`self` is just a name. In `expand()` you are rebinding the name `self` away from the object and to a new Expr instance.
If you want to change `self` the original object you have to do something like:
def expand(self):
self.op = choice('+-*/')
self.val = choice('12345')
--
~Ethan~
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