dictionary with object's method as thier items

[noro]

Is it possible to do the following:

for a certain class:

----------------------------
class C:

def func1(self):
pass
def func2(self):
pass
def func4(self):
pass

obj=C()
----------------------------

by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

and so i could access every method of instances of C, such as obj with
sometiing like:
(i know that this syntax wont work )

obj.(d['function one'])
obj.(d['function two'])
etc..
thanks

[John Purser]

On 30 Aug 2006 06:35:17 -0700
"noro" <am******@gmail.comwrote:

Is it possible to do the following:

for a certain class:

----------------------------
class C:

def func1(self):
pass
def func2(self):
pass
def func4(self):
pass

obj=C()
----------------------------

by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

and so i could access every method of instances of C, such as obj with
sometiing like:
(i know that this syntax wont work )

obj.(d['function one'])
obj.(d['function two'])
etc..

Sure. But the syntax would be:
d['function one'] = c.func1
d['function one']()

I'm not sure what this gets you but it works.

John Purser

[Roberto Bonvallet]

noro wrote:

Is it possible to do the following:

for a certain class:

[...]

by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

and so i could access every method of instances of C

Something like this?

>>class C:

.... def f1(self):
.... print "i'm one"
.... def f2(self):
.... print "i'm two"
....

>>obj = C()
d = {'one': obj.f1, 'two': obj.f2}
d['one']()

i'm one

>>d['two']()

i'm two

--
Roberto Bonvallet

[Bruno Desthuilliers]

noro wrote:

Is it possible to do the following:

for a certain class:

----------------------------
class C:

def func1(self):
pass
def func2(self):
pass
def func4(self):
pass

obj=C()
----------------------------

by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

and so i could access every method of instances of C, such as obj with
sometiing like:
(i know that this syntax wont work )

obj.(d['function one'])
obj.(d['function two'])
etc..

Let me guess... What you want to is in fact to call a method by it's
name ? If so, getattr(obj, name) is your friend:

class Knight(object):
def __init__(self):
self._saywhat = "ni"
self._wantwhat ="shrubbery"

def says(self):
return self._saywhat

def wants(self):
return self._wantwhat

k = Knight()

print getattr(k, "says")()
print getattr(k, "wants")()

HTH
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'o****@xiludom.gro'.split('@')])"

[Georg Brandl]

noro wrote:

Is it possible to do the following:

for a certain class:

----------------------------
class C:

def func1(self):
pass
def func2(self):
pass
def func4(self):
pass

obj=C()
----------------------------

by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

Perhaps this:

>>class C:

.... def function(self, arg):
.... print arg
....

>>obj = C()
d = C.__dict__
d['function'](obj, 42)

42

>>>

Georg

[Gabriel Genellina]

At Wednesday 30/8/2006 10:35, noro wrote:

>for a certain class:
by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

and so i could access every method of instances of C, such as obj with
sometiing like:
(i know that this syntax wont work )

obj.(d['function one'])
obj.(d['function two'])

You can use dir(obj) to get its list of attributes (including method
names) then use getattr to invoke the method.

methodname='func1'
getattr(obj,methodname)()

See the inspect module too.
Gabriel Genellina
Softlab SRL

__________________________________________________
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Todo lo que querías saber, y lo que ni imaginabas,
está en Yahoo! Respuestas (Beta).
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http://www.yahoo.com.ar/respuestas

[noro]

great that is what i looked for.

>>class C:

... def function(self, arg):
... print arg
...

>>obj = C()
>>d = C.__dict__
>>d['function'](obj, 42)

42

this allows me the access the same method in a range of objects.

i can put all the functions i need in a dictionary as items, and the
vars as keys, and then call them for all objects that belong to a
class..

something like this

----------------------------------------------------
class C:

#object vars
self.my_voice
self.my_size
self.my_feel

# a method that do somthing, that might give different result for
different objects
getVoice(self):
return(self.my_voice+'WOW')

getSize(self):
return(self.my_size*100)

getFeel(self):
return(self.my_feel)
#create the dictionary with a reference to the class methode
dic={'voice':C.getVoice,'size':C.getSize,'feel':C. getFeel}
# create array of 10 different objects
cArray = []
for i in range(10)
cArray.append(C())
cArray[0].my_size=i

# choose the function you need, and get the result
choice=WHAT EVER KEY (e.g 'size')
for i in range(10)
print dic[choice](cArray[i])

#or even print all the values of all objects. if i ever want to print
diffenet valuse i only need
# to change the dictionary, nothing else...
for choice in dic:
for i in range(10)
print dic[choice](cArray[i])
---------------------------------------------------------------
i totaly forget about the "self" argument in every method...

a. is the main reason "self is there, or is it only a side effect?
b. what do you think about this code style? it is not very OOP, but i
cant see how one can do it other wise, and be able to control the
function printed out with something as easy as dictionary..

Georg Brandl wrote:

noro wrote:

Is it possible to do the following:

for a certain class:

----------------------------
class C:

def func1(self):
pass
def func2(self):
pass
def func4(self):
pass

obj=C()
----------------------------

by some way create a dictionary that look somthing like that:

d= {'function one': <reference to C.func1()>, \
'function two': <reference to C.func2()>, \
'function three': <reference to C.func3()>}

Perhaps this:

>>class C:

... def function(self, arg):
... print arg
...

>>obj = C()
>>d = C.__dict__
>>d['function'](obj, 42)

42

>>>

Georg

[Bruno Desthuilliers]

noro wrote:

great that is what i looked for.

Hmmm... Not quite sure

>>>class C:

... def function(self, arg):
... print arg
...

> >>obj = C()
d = C.__dict__
d['function'](obj, 42)

42

this allows me the access the same method in a range of objects.

class Obj(object):
def __init__(self, num):
self.num = num
def method(self):
return "in %s.method" % self

for obj in [Obj(i) for i in range(10)]:
print getattr(obj, "method")()

i can put all the functions i need in a dictionary as items, and the
vars as keys, and then call them for all objects that belong to a
class..

something like this

----------------------------------------------------
class C:

#object vars
self.my_voice
self.my_size
self.my_feel

# a method that do somthing, that might give different result for
different objects
getVoice(self):
return(self.my_voice+'WOW')

getSize(self):
return(self.my_size*100)

getFeel(self):
return(self.my_feel)
#create the dictionary with a reference to the class methode
dic={'voice':C.getVoice,'size':C.getSize,'feel':C. getFeel}
# create array of 10 different objects
cArray = []
for i in range(10)
cArray.append(C())
cArray[0].my_size=i

# choose the function you need, and get the result
choice=WHAT EVER KEY (e.g 'size')
for i in range(10)
print dic[choice](cArray[i])

#or even print all the values of all objects. if i ever want to print
diffenet valuse i only need
# to change the dictionary, nothing else...
for choice in dic:
for i in range(10)
print dic[choice](cArray[i])

---------------------------------------------------------------
i totaly forget about the "self" argument in every method...

???

a. is the main reason "self is there, or is it only a side effect?

I'm not sure I understand your question.

b. what do you think about this code style?

Don't ask me if you don't want to get hurt !-)

it is not very OOP,

This is not a problem - Python doesn't forces you that much into OO.

but i
cant see how one can do it other wise,

using getattr(<object>, <attrname>[,<default>])

and be able to control the
function printed out with something as easy as dictionary..

Here's a somewhat more pythonic way to do the same thing (NB : not tested):

# a simple decorator
def choice(func):
func.is_choice = True
return func

# helper func
def is_choice(obj):
return callable(obj) and getattr(obj, 'is_choice', False)

# braindead metaclass
class ChoicesMeta(type):
def __init__(cls, name, bases, classdict):
cls.choices = [name for name, attrib in classdict.items() \
if is_choice(attrib)]

# our class...
class Foo(object):
__metaclass__ = ChoicesMeta

def __init__(self, num):
self.num = num

# mark the method as usable in choices
@choice
def bar(self):
return "foo #%s.bar" % self.num

@choice
def baaz(self):
return "foo #%s.baaz" % self.num

# let's test:
foos = [Foo(i) for i in range(10)]

choice = <whatever name existing in Foo.choices>
for foo in foos:
print getattr(foo, choice)()
HTH

--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'o****@xiludom.gro'.split('@')])"