Reference to self not passed to member function

[James Stroud]

Hello All,

I did this:

py> class bob(object):
.... def __init__(self,**kwargs):
.... for fname,func in kwargs.items():
.... setattr(self, fname, lambda *args : func(*args))
....
py> def doit():
.... print "wuzzup?"
....
py> abob = bob(doit=doit)
py>
py> abob.doit()
wuzzup?


Much to my surprise, this works fine.

My questions:

1. What exactly is going on?
2. How can I get ref to self passed to doit() if I want it to? This:

abob.doit(abob)

seems like the hard way

Any ideas?

James


--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

 

[wittempj]

I think it is more clear to rephrase your code as:
-#!/usr/bin/env python
-class bob(object):
- def __init__(self,**kwargs):
- print kwargs
- for fname,func in kwargs.items():
- setattr(self, fname, lambda *args : func(*args))
-
-def doit():
- print "wuzzup?"
-
-
-abob = bob(sayyoudo=doit)
-
-abob.sayyoudo()
outpu is now:
martin@ubuntu:~$ ./test.py
{'sayyoudo': <function doit at 0xb7dfcdf4>}
wuzzup?
martin@ubuntu:~$

so property sayyoudo points to method doit

 

[Scott David Daniels]

Hello All,

I did this:

py> class bob(object):
... def __init__(self,**kwargs):
... for fname,func in kwargs.items():
... setattr(self, fname, lambda *args : func(*args))
...
py> def doit():
... print "wuzzup?"
...
py> abob = bob(doit=doit)
py>
py> abob.doit()
wuzzup?

Much to my surprise, this works fine.
> 1. What exactly is going on?

This behavior shouldn't surprise you. You stored a function as
an attribute. In fact you could have simply done:
py> class bob(object):
.... def __init__(self,**kwargs):
.... for fname, function in kwargs.items():
.... setattr(self, fname, function)

2. How can I get ref to self passed to doit() if I want it to? This:
abob.doit(abob)

py> import new
py> class carol(object):
.... def __init__(self, **kwargs):
.... for name, method in kwargs.items():
.... setattr(self, name,
.... new.instancemethod(method, self, carol))

This should behave as you prefer.


--Scott David Daniels
(e-mail address removed)

 

[James Stroud]

Thanks to both Scott and Fredrik.

James

This behavior shouldn't surprise you. You stored a function as
an attribute. In fact you could have simply done:
py> class bob(object):
... def __init__(self,**kwargs):
... for fname, function in kwargs.items():
... setattr(self, fname, function)


py> import new
py> class carol(object):
... def __init__(self, **kwargs):
... for name, method in kwargs.items():
... setattr(self, name,
... new.instancemethod(method, self, carol))

This should behave as you prefer.


--Scott David Daniels
(e-mail address removed)

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/