How to call module functions inside class instance functions?

[beginner]

Hi Everyone,

I have encountered a small problems. How to call module functions
inside class instance functions? For example, calling func1 in func2
resulted in a compiling error.

"my module here"

def func1():
print "hello"

class MyClass:
def func2():
#how can I call func1 here.
func1() #results in an error


Thanks,
Geoffrey

 

[Zentrader]

Hi Everyone,

I have encountered a small problems. How to call module functions
inside class instance functions? For example, calling func1 in func2
resulted in a compiling error.

"my module here"

def func1():
print "hello"

class MyClass:
def func2():
#how can I call func1 here.
func1() #results in an error

Thanks,
Geoffrey

You might want to check one of the online tutorials about how to code
classes. Google or look at "Learning Python" here http://www.python-eggs.org/
def func1():
print "hello"

class MyClass:
def func2(self):
#how can I call func1 here.
func1() #results in an error

MC= MyClass()
MC.func2()

 

[Steve Holden]

Hi Everyone,

I have encountered a small problems. How to call module functions
inside class instance functions? For example, calling func1 in func2
resulted in a compiling error.

"my module here"

def func1():
print "hello"

class MyClass:
def func2():
#how can I call func1 here.
func1() #results in an error

If you had bothered to include the error message it would have been
obvious that the problem with your code isn't in body of the method at
all - you have failed to include an argument to the method to pick up
the instance on which the method is called. I am guessing that when you
create an instance and call its func2 method you see the message

Traceback (most recent call last):
File "test07.py", line 12, in <module>
myInstance.func2()
TypeError: func2() takes no arguments (1 given)

which would have been a very useful clue. Please include the traceback
in future! Here's a version of your program that works.

sholden@bigboy ~/Projects/Python
$ cat test07.py
"my module here"

def func1():
print "hello"

class MyClass:
def func2(self):
#how can I call func1 here.
func1() #results in an error

myInstance = MyClass()
myInstance.func2()

sholden@bigboy ~/Projects/Python
$ python test07.py
hello

regards
Steve
--
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://del.icio.us/steve.holden
--------------- Asciimercial ------------------
Get on the web: Blog, lens and tag the Internet
Many services currently offer free registration
----------- Thank You for Reading -------------

 

[Lawrence Oluyede]

I have encountered a small problems. How to call module functions
inside class instance functions? For example, calling func1 in func2
resulted in a compiling error.

"my module here"

def func1():
print "hello"

class MyClass:
def func2():
#how can I call func1 here.
func1() #results in an error

rhymes@groove ~ % cat t.py
def func1():
print "hello"

class MyClass:
def func2():
func1()
rhymes@groove ~ % python -c "import t"
rhymes@groove ~ %

As you can see there no compiling error, because the syntax is correct,
you'll eventually get a runtime error like this:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: func2() takes no arguments (1 given)

That's because you left out the "self" argument in the definition of
"func2()". This version is correct:

--
def func1():
print "hello"

class MyClass(object):
def func2(self):
func1()

c = MyClass()
c.func2()
--

rhymes@groove ~ % python tcorrect.py
hello


HTH

 

[beginner]

If you had bothered to include the error message it would have been
obvious that the problem with your code isn't in body of the method at
all - you have failed to include an argument to the method to pick up
the instance on which the method is called. I am guessing that when you
create an instance and call its func2 method you see the message

Traceback (most recent call last):
File "test07.py", line 12, in <module>
myInstance.func2()
TypeError: func2() takes no arguments (1 given)

which would have been a very useful clue. Please include the traceback
in future! Here's a version of your program that works.

sholden@bigboy ~/Projects/Python
$ cat test07.py
"my module here"

def func1():
print "hello"

class MyClass:
def func2(self):
#how can I call func1 here.
func1() #results in an error

myInstance = MyClass()
myInstance.func2()

sholden@bigboy ~/Projects/Python
$ python test07.py
hello

regards
Steve
--
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://del.icio.us/steve.holden
--------------- Asciimercial ------------------
Get on the web: Blog, lens and tag the Internet
Many services currently offer free registration
----------- Thank You for Reading -------------- Hide quoted text -

- Show quoted text -

I apologize for not posting the exact code and error message. The
missing "self" is due to a typo of mine. It is not really the problem
I am encountering.

testmodule.py
-----------------
"""Test Module"""

def __module_level_func():
print "Hello"

class TestClass:
def class_level_func(self):
__module_level_func()


main.py
------------------
import testmodule

x=testmodule.TestClass()
x.class_level_func()


The error message I am encountering is: NameError: global name
'_TestClass__module_level_func' is not defined

I think it has something to do with the two underscores for
__module_level_func. Maybe it has something to do with the python
implementation of the private class level functions.

By the way, the reason I am naming it __module_level_func() is because
I'd like __module_level_func() to be private to the module, like the C
static function. If the interpreter cannot really enforce it, at least
it is some sort of naming convention for me.

Thanks,
Geoffrey

 

[beginner]

You might want to check one of the online tutorials about how to code
classes. Google or look at "Learning Python" herehttp://www.python-eggs.org/
def func1():
print "hello"

class MyClass:
def func2(self):
#how can I call func1 here.
func1() #results in an error

MC= MyClass()
MC.func2()- Hide quoted text -

- Show quoted text -

Thanks for your help. The missing "self" is a typo of mine. It is not
the problem I am encountering. Sorry for posting the wrong code.

 

[Zentrader]

By the way, the reason I am naming it __module_level_func() is because

I'd like __module_level_func() to be private to the module, like the C
static function. If the interpreter cannot really enforce it, at least
it is some sort of naming convention for me.

re the above: set file permissions for testmodule.py to limit access.
IMHO it is a better solution.

 

[Alex Martelli]

testmodule.py
-----------------
"""Test Module"""

def __module_level_func():
print "Hello"

class TestClass:
def class_level_func(self):
__module_level_func()


main.py
------------------
import testmodule

x=testmodule.TestClass()
x.class_level_func()


The error message I am encountering is: NameError: global name
'_TestClass__module_level_func' is not defined

I think it has something to do with the two underscores for
__module_level_func. Maybe it has something to do with the python
implementation of the private class level functions.

By the way, the reason I am naming it __module_level_func() is because
I'd like __module_level_func() to be private to the module, like the C
static function. If the interpreter cannot really enforce it, at least
it is some sort of naming convention for me.

The two underscores are exactly the cause of your problem: as you see in
the error message, the compiled has inserted the CLASS name (not MODULE
name) implicitly there. This "name mangling" is part of Python's rules.

Use a SINGLE leading underscore (NOT double ones) as the "sort of naming
convention" to indicate privacy, and Python will support you (mostly by
social convention, but a little bit technically, too); use a different
convention (particularly one that fights against the language rules;-)
and you're "fighting city hall" to no good purpose and without much hope
of achieving anything whatsoever thereby.


Alex