print object/instance name in python

Question

I was wondering if there is a way to print the object name in python as a string. For example I want to be able to say ENEMY1 has 2 hp left or ENEMY2 has 4 hp left. Is there a way of doing that?\

class badguy: def __init__(self): self.hp = 4 def attack(self): print("hit") self.hp -= 1 def still_alive(self): if self.hp <=0: print("enemy destroyed") else : print (str(self.hp) + " hp left") # creating objects enemy1 = badguy() enemy2 = badguy() enemy1.attack() enemy1.attack() enemy1.still_alive() enemy2.still_alive()

You can, but you may find that it makes more sense to just have a name field on the badguy class. Reflecting against variable names is almost always a bad idea. Plus, what if you had a huge list of enemies? — Athena
– Athena, Commented Jul 26, 2016 at 20:10
Objects don't have unique names. If you do newname = enemy1, then what is the "name" of that object? — BrenBarn
– BrenBarn, Commented Jul 26, 2016 at 20:11
Most objects don't have names. Variables have names, but there is no one-to-one correspondence between variables and objects. — user2357112
– user2357112, Commented Jul 26, 2016 at 20:12
It's actually impossible to do this, since multiple "names" can refer to the same object: a = object(); b = a; print(a is b) # True — Zac Crites
– Zac Crites, Commented Jul 26, 2016 at 20:26
Does this answer your question? method to print name of an instance of a class — ThinkingInBits
– ThinkingInBits, Commented Sep 10, 2023 at 7:20

ospahiu · Accepted Answer · 2016-07-26 20:57:55Z

A much better design principle is not to rely on the specific name of the object as shown below:

class badguy(object): def __init__(self): pass b = badguy() print b >>> <__main__.badguy object at 0x7f2089a74e50> # Not a great name huh? :D

This can lead to a whole wealth of issues with assignment binding, referencing, and most importantly does not allow you to name your objects per user or program choice.

Instead add an instance variable to your class called self._name (9.6 Classes - Private Variables) or self.name if you want to allow access outside the scope of the class (in this example, you can name it anything). Not only is this more Object-Oriented design, but now you can implement methods like __hash__ to be able to create a hash based on a name for example to use an object as a key (there are many more reasons why this design choice is better!).

class badguy(object): def __init__(self, name=None): self.hp = 4 self._name = name @property def name(self): return self._name @name.setter def name(self, name): self._name = name def attack(self): print("hit") self.hp -= 1 def still_alive(self): if self.hp <=0: print("enemy destroyed") else : print ("{} has {} hp left.".format(self.name, self.hp))

Sample output:

b = badguy('Enemy 1') print b.name >>> Enemy 1 b.still_alive() >>> Enemy 1 has 4 hp left. b.name = 'Enemy One' # Changing our object's name. b.still_alive() >>> Enemy One has 4 hp left.

Good answer, but my eyes bleed at set_name(..). Can you please use @property instead?
@SuperSaiyan Changed it aha, I agree @property is the way to go, simply didn't include it in the answer originally.

user94559 · Accepted Answer · 2016-07-26 20:26:34Z

You'd have to first give them names. E.g.

class badguy: def __init__(self, name): self.hp = 4 self.name = name def attack(self): print("hit") self.hp -= 1 def still_alive(self): if self.hp <=0: print("enemy destroyed") else : print (self.name + " has " + str(self.hp) + " hp left") # creating objects enemy1 = badguy('ENEMY1') enemy2 = badguy('ENEMY2') enemy1.attack() enemy1.attack() enemy1.still_alive() enemy2.still_alive()

I see the issue not putting in the self, name. That does make it easier to use, although I was hoping that the actual variable name could have been used so there isn't the redundancy of making the object name and then naming it again in quotes. Thank you.
@netrate As commenters have pointed out, there's no such thing as an "object name." The variable has a name, but there can be lots of variables pointing to the same object, so how would you decide which one to use?

TheoRet · Accepted Answer · 2018-03-17 02:01:46Z

I have posted a complete solution here:

https://stackoverflow.com/a/49331683/7386061

It works without parameters. For example you could just do:

class badguy(RememberInstanceCreationInfo): def __init__(self): super().__init__() self.hp = 4 def attack(self): print("hit") self.hp -= 1 def still_alive(self): if self.hp <=0: print("enemy destroyed") else : print (self.creation_name + " has " + str(self.hp) + " hp left") enemy1 = badguy() enemy2 = badguy() enemy1.attack() enemy1.attack() enemy1.still_alive() enemy2.still_alive() out: hit out: hit out: enemy1 has 2 hp left out: enemy2 has 4 hp left

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