Check whether method is called directly or by another method

Question

I'd like to know whether my method is called by the user directly or by another method. To make it less abstract:

class myclass():
    def __init__(self, ...):
        ....

    def method1(self, ...):
        ...
        --- some if statement --
        print "Hello"
        return something

    def callmethod(self, ...):
        x = self.method1(...)
        return x*2

 myinstance = myclass(...)
 myinstance.method1(...)
 --> 'Hello'
 myinstance.callmethod(...)
 --> -

Hopefully my class makes clear what I'd like to do: When the user calls 'method1' the print statement shall be executed but if 'method1' is called by another method like 'callmethod' the print statement shall not be executed. Therefore I need 'some if statement' which checks whether 'method1' is called by the user directly or by another method. Thanks for you help!

score 4 · Accepted Answer · answered Mar 22 '17 at 15:06

No, and you don't want to do this.

If you want to change behaviour depending on the way a method is called, then you need to use a parameter. You can use a default value to make this simpler, for example:

def method1(self, do_print=True):
    ...
    if do_print:
        print "Hello"
    return something

def callmethod(self, ...):
    x = self.method1(do_print=False)
    return x*2

Now, calling myinstance.method1() will print, whereas myinstance.callmethod() will not.

score 1 · Answer 2 · edited May 23 '17 at 12:10

It's actually achievable using the python inspector, like e.g.:

import inspect

class myclass():
    def __init__(self):
        pass

    def method1(self):
        (frame, filename, line_number, function_name, lines, index) = inspect.getouterframes(inspect.currentframe())[1]
        if function_name == '<module>':
            print "Hello"
        return 2

    def callmethod(self):
        x = self.method1()
        return x*2

myinstance = myclass()
myinstance.method1()
myinstance.callmethod()

but I agree with Daniel it's not an elegant way to achieve the result as it hides some behaviour.

For further details also see: this post

Check whether method is called directly or by another method

2 Answers2