How can I programmatically find the name of a method from within that method?

[kj7ny]

Is there a way that I can programmatically find the name of a method I
have created from within that method? I would like to be able to log
a message from within that method (def) and I would like to include
the name of the method from which it was written without having to
hard-code that value in every message string. While we're at it, is
there a way to programmatically get the name of the class and the
module while I'm at it?

Thanks,

 

[Jay Loden]

Is there a way that I can programmatically find the name of a method I
have created from within that method? I would like to be able to log
a message from within that method (def) and I would like to include
the name of the method from which it was written without having to
hard-code that value in every message string. While we're at it, is
there a way to programmatically get the name of the class and the
module while I'm at it?

This is a frequently asked question around here

You should search the list archives for past threads, e.g:
http://aspn.activestate.com/ASPN/Mail/Message/python-list/3542665

-Jay

 

[kj7ny]

This is a frequently asked question around here

You should search the list archives for past threads, e.g:http://aspn.activestate.com/ASPN/Mail/Message/python-list/3542665

-Jay

Thanks for the link. I had actually searched the past threads, but
apparently didn't enter the right search criteria because I did not
find that thread. Or, that thread isn't findable by searching Google
groups?

I tried the example in the interpreter and it appears to work.
Despite my years and years of programming in python, I am a bit
baffled by the example though. What is @checkPrivs (see example
copied below from other post)? In fact... how does the thing work at
all?

------------------------------------------
def checkPrivs(fn):
fnName = fn.func_name
def restricted(*args):
print "about to call function", fnName
if fnName in listOfAllowedFunctions:
return fn(*args)
else:
raise KeyError("you don't have sufficient privileges to do
THAT")
return restricted

listOfAllowedFunctions = ['add','subtract']

@checkPrivs
def add(a,b):
return a+b

@checkPrivs
def subtract(a,b):
return a-b

@checkPrivs
def multiply(a,b):
return a*b

add(1,2)
subtract(4,1)
multiply(3,2)

 

[Peter Otten]

What is @checkPrivs (see example copied below from other post)? In
fact... how does the thing work at all?

@checkPrivs
def add(a,b):
return a+b

@... is called a decorator and is just a fancy way of writing

def add(a, b):
return a+b
add = checkPrivs(add)

Peter

 

[Tony]

@... is called a decorator and is just a fancy way of writing

def add(a, b):
return a+b
add = checkPrivs(add)

Peter

Is this cheating?

class a:


def square(self, x):

print 'executing:', dir(self)[-1]
print x*x
def cube(self, x):
print 'executing:', dir(self)[-2]
print x*x*x

b=a()



b.square(3)
b.cube(3)
Output:

PyMate r6780 running Python 2.3.5 (python)
executing: square
9
executing: cube
27

 

[Peter Otten]

Is this cheating?

Isn't it harder to calculate the magic indices than just writing down the
names twice?

class a:
        def square(self, x):
                print 'executing:', dir(self)[-1]
                print x*x
        def cube(self, x):
                print 'executing:',     dir(self)[-2]
                print x*x*x

b=a()
b.square(3)
b.cube(3)
Output:

PyMate r6780 running Python 2.3.5 (python)
executing: square
9
executing: cube
27

Is this cheating?

No, just wrong.
.... def alpha(self): return dir(self)[-2]
.... def gamma(self): return dir(self)[-1]
....('beta', 'gamma')

Peter

 

[Tony]

No, just wrong.

... def alpha(self): return dir(self)[-2]
... def gamma(self): return dir(self)[-1]
...>>> a = A()
('beta', 'gamma')

Peter

Only wrong if the function is only to write its own name. if it does
something else as well, seems to work:

class a:

def square(self, x):
print 'executing:', dir(self)[-1]
print x*x
def cube(self, x):
print 'executing:', dir(self)[-2]
print x*x*x

b=a()

b.cube(4),b.square(2)
b.c =4
b.cube(3), b.cube(2)



executing: cube
64
executing: square
4
executing: cube
27
executing: cube
8

cheers

 

[faulkner]

Is there a way that I can programmatically find the name of a method I
have created from within that method? I would like to be able to log
a message from within that method (def) and I would like to include
the name of the method from which it was written without having to
hard-code that value in every message string. While we're at it, is
there a way to programmatically get the name of the class and the
module while I'm at it?

Thanks,

def foo():
print sys._getframe(0).f_code.co_name

most of the darkest magic of python is in the frames returned by
sys._getframe.

 

[faulkner]

def foo():
print sys._getframe(0).f_code.co_name

most of the darkest magic of python is in the frames returned by
sys._getframe.

sorry for the double-post. i forgot to answer the rest of the
question.

class a:
def b(self, *a):
print sys._getframe(0).f_code.co_name
print self.__class__.__name__
print getattr(self,
sys._getframe(0).f_code.co_name).im_class.__name__
print self.__class__.__module__

def log(f):
def newf(*a, **kw):
if a and f.func_code.co_varnames[0] == 'self': print '%s.%s.%s
%r %r' % (a[0].__class__.__module__, a[0].__class__.__name__,
f.func_name, a, kw)
else: print '%s.%s %r %r' % (f.func_globals['__name__'],
f.func_name, a, kw)
f(*a, **kw)
newf.__name__ = f.__name__
newf.__doc__ = f.__doc__
return newf

you can find more interesting attributes of frame and function objects
using the builtin dir function.

 

[Peter Otten]

No, just wrong.

class A:

... def alpha(self): return dir(self)[-2]
... def gamma(self): return dir(self)[-1]
...>>> a = A()

a.alpha(), a.gamma() ('alpha', 'gamma')
a.beta = 42
a.alpha(), a.gamma()

('beta', 'gamma')

Peter

Only wrong if the function is only to write its own name. if it does
something else as well, seems to work:

class a:

        def square(self, x):
                print 'executing:', dir(self)[-1]
                print x*x
        def cube(self, x):
                print 'executing:',     dir(self)[-2]
                print x*x*x

b=a()

b.cube(4),b.square(2)
b.c =4
b.cube(3), b.cube(2)

You mean

b.cube(3), b.square(2)

executing: cube
64
executing: square
4
executing: cube
27
executing: cube
8

Yeah, cargo cult programming, I love it.

dir() sorts attribute names alphabetically. Therefore the tail of the list
you are accessing will only be altered if you choose a name >
min(other_names), i. e. a name that comes after "cube" in the alphabet. Try
setting

b.root = 42

if you don't believe me.

Peter