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Date: Fri, 28 Nov 2014 11:04:26 +0800
Subject: Re: Can you use self in __str__
From: Shiyao Ma <i@introo.me>
To: Seymore4Head <Seymore4Head@hotmail.invalid>
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2014-11-28 9:26 GMT+08:00 Seymore4Head <Seymore4Head@hotmail.invalid>:
>     def __str__(self):
>         s = "Hand contains "
>         for x in self.hand:
>             s = s + str(x) + " "
>         return s
>
> This is part of a Hand class.  I need a hand for the dealer and a hand
> for the player.
> dealer=Hand()
> player=Hand()
> This prints out 'Hand contains " foo bar
> for both the dealer's hand and the player's hand.
>
> Is there a way to include "self" in the __string__ so it reads
> Dealer hand contains foo bar
> Player hand contains foo bar

I bet you want the object name (aka, dealer, player) be included in
the string 's'.
To that end, you need to access the namespace where 'self' is in.
But I dunno where the namespace 'self' resides in.
Does PyObject has a field to store the namespace of an object?
Appreciated if anyone could
inform me on this.

Now, make a little assumption that the instance lives in the module
level. Then we can do
this:

#!/usr/bin/env python

class Hand(object):
def __init__(self):
self.hand = [1, 2, 3, 4]

def __str__(self):
s = self._myname + " hand contains "
for x in self.hand:
s = s + str(x) + " "
return s

@property
def _myname(self):
# get the module
mod = self.__module__
import sys
ns = vars(sys.modules[mod])
# NB only works the instance is at the module level
for name, obj in ns.iteritems():
if id(obj) == id(self):
break
else:
#nothing found
return ""
return name

John = Hand()
print(John)

# this prints
# John hand contains 1 2 3 4

bad indentation with my wasavi plugin, see paste:

https://bpaste.net/show/f5b86957295f


What if it's in the local namespace of a function or method? IDK, try
to get that thing first.


Regards






--

吾輩は猫である。ホームーページはhttp://introo.me。