How to get the object instance by its variable

Question

Suppose I will send self.f to a global method,

def write_to_report(file_hdlr, content):

If I want get the what the object is the file_hdlr belonged to.

How to get it ? Because I need to know the file_hanlder is belonging which Class, and use the class name to do somthing

def write_to_report(file_hdlr, content):
    file_hdlr.__self__ # ??? NO

CODE

class MemoryInfo(threading.Thread):        
    def __init__(self, config):
        self.f = get_export_file_hdlr(self.__class__.__name__)

class CPUInfo(threading.Thread):        
    def __init__(self, config):
        self.f = get_export_file_hdlr(self.__class__.__name__)

Objects do not have an implicit pointer to their "parent". If you think about it, the concept of "parent" does not even make sense, because when a reference is passed, a copy of the reference is made, and this copy is just as valid as the original reference. Now your object belongs to two different objects. — merlin2011
– merlin2011, Commented Jun 18, 2014 at 7:08

Chris Clarke · Accepted Answer · 2014-06-18 08:57:59Z

1

You can't.

A different approach:

class ReportWriterMixin(object):
    def write_to_report(self):
        this_class = self.__class__
        # do thing with self.f based on this_class

class CPUInfo(threading.Thread, ReportWriterMixin):        
    def __init__(self, config):
        self.f = get_export_file_hdlr(self.__class__.__name__)
        self.write_to_report()

This way, while your method is no longer "global", it can be made available to any class you like

answered Jun 18, 2014 at 8:57

Chris Clarke

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Comments

juankysmith · Accepted Answer · 2014-06-18 07:07:39Z

0

If you want to know the type of file_hdlr variable, you can use function type:

file_hdlr_type = type(file_hdlr)

answered Jun 18, 2014 at 7:07

juankysmith

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2 Comments

merlin2011 Over a year ago

He's asking how he can get the original self reference that contained file_hdlr....

juankysmith Over a year ago

Sorry, I didn't understand

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