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How to get and print Python class Attributes

In this article, we are going to learn How to get and print Python class Attributes . The built-in attributes of a Python class and Python class Attribute how to get and print. When we declare a Python class, it comes with some built-in attributes that we get by default. These built-in attributes of Python classes are very useful and provide us a lot of information about that class. All these attributes have special representation and they all start with the double underscore “__”.

So let us start learning about these Python class Attributes in detail with the help of code examples.

First of all, let us see what are the attributes that we get in Python classes:

List of attribute in Python classes

1. __dict__ Dictionary

The Dictionary attribute of Python classes contains the information about the namespace to which this class belongs. Namespaces are the collections or modules scope definition that can include many classes inside it. So with the help of the Dictionary attribute, we can get this information about the class.

2. __doc__ Class documentation

Class documentation attribute gives us the class string doc information to us. This attribute gives us this information if this was defined by the person who wrote the class. If there is no string available in this then it returns none. In the class definition, class documentation is the very first line. This is not a mandatory requirement in class definition but it is good practice to have this. This helps others to understand what this class is about and what kind of functionality this class implements.

5.__bases__ Base class list

Inheritance is a very useful feature of OOPs and it provides us the concept of Base and derived classes. Base class list attributes help us to find out the Base class details of any class. It provides us this information as a tuple containing the base classes, in the order of their occurrence in the base class list. The object class is the base of all the classes in Python so this will return the object even if there is no base class defined by you.

Now let us jump to a Code example and demo of each of these class attributes. To start with, let us first define a class that we will use to understand all these attributes.

Program to get and print Python class Attributes

class Student: 'this is student class' studentcount = 0 def __init__(self, name, standard): self.name = name self.standard = standard Student.studentcount += 1 def displayStuCount(self): print ("Total Students %d" % Student.studentcount) def displayEmployee(self): print ("StuName : ", self.name, ", standard: ",self.standard) stud1 = Student("max", 5) stud2 = Student("Rack", 10) print ("Student.__doc__:", Student.__doc__) print ("Student.__name__:", Student.__name__) print ("Student.__module__:", Student.__module__) print ("Student.__bases__:", Student.__bases__) print ("\nStudent.__dict__:\n", Student.__dict__)

Student.__doc__: this is student class Student.__name__: Student Student.__module__: __main__ Student.__bases__: (,) Student.__dict__: , 'displayStuCount': , 'displayEmployee': , '__dict__': , '__weakref__': >

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Python: Print an Object’s Attributes

In this tutorial, you’ll learn how to use Python to print an object’s attributes. Diving into the exciting world of object-oriented programming can seem an overwhelming task, when you’re just getting started with Python. Knowing how to access an object’s attributes, and be able to print all the attributes of a Python object, is an important skill to help you investigate your Python objects and, perhaps, even do a little bit of troubleshooting.

We’ll close the tutorial off by learning how to print out the attributes in a prettier format, using the pprint module!

Let’s take a look at what you’ll learn!

The Quick Answer: Use the dir() Function

What are Python Objects?

Python is an object-oriented language – because of this, much of everything in Python is an object. In order to create objects, we create classes, which are blueprints for objects. These classes define what attributes an object can have and what methods an object can have, i.e., what it can do.

Let’s create a fairly simple Python class that we can use throughout this tutorial. We’ll create a Dog class, which will a few simple attributes and methods.

class Dog: def __init__(self, name, age, puppies): self.name = name self.age = age self.puppies = puppies def birthday(self): self.age += 1 def have_puppies(self, number_puppies): self.have_puppies += number_puppies

What we’ve done here, is created our Dog class, which has the instance attributes of name , age , and puppies , and the methods of birthday() and have_puppies() .

Let’s now create an instance of this object:

teddy = Dog(name='Teddy', age=3, puppies=0)

We now have a Python object of the class Dog , assigned to the variable teddy . Let’s see how we can access some of its object attributes.

What are Python Object Attributes?

In this section, you’ll learn how to access a Python object’s attributes.

Based on the class definition above, we know that the object has some instance attributes – specifically, name, age, and puppies.

We can access an object’s instance attribute by suffixing the name of the attribute to the object.

Let’s print out teddy’s age:

print(teddy.name) # Returns: Teddy

There may, however, be times when you want to see all the attributes available in an object. In the next two sections, you’ll learn how to find all the attributes of a Python object.

Use Python’s dir to Print an Object’s Attributes

One of the easiest ways to access a Python object’s attributes is the dir() function. This function is built-in directly into Python, so there’s no need to import any libraries.

Let’s take a look at how this function works:

# Printing an object's attributes using the dir() function attributes = dir(teddy) # Returns: # ['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'age', 'birthday', 'have_puppies', 'name', 'puppies']

We can see here that this prints out of all the attributes of a Python object, including the ones that are defined in the class definition.

The dir() function returns.a list of the names that exist in the current local scope returns the list of the names of the object’s valid attributes.

Let’s take a look at the vars() function need to see a more in-depth way to print an object’s attributes.

Use Python’s vars() to Print an Object’s Attributes

The dir() function, as shown above, prints all of the attributes of a Python object. Let’s say you only wanted to print the object’s instance attributes as well as their values, we can use the vars() function.

print(vars(teddy)) # Same as print(teddy.__dict__) # Returns: #

We can see from the above code that we’ve returned a dictionary of the instance attributes of our object teddy .

The way that this works is actually by accessing the __dict__ attribute, which returns a dictionary of all the instance attributes.

We can also call this method on the class definition itself. Let’s see how that’s different from calling it on an object:

print(vars(Dog)) # Returns # , 'birthday': , 'have_puppies': , '__dict__': , '__weakref__': , '__doc__': None>

We can see here that this actually returns significantly more than just calling the function on an object instance.

The dictionary also includes all the methods found within the class, as well as the other attributes provided by the dir() method.

If we wanted to print this out prettier, we could use the pretty print pprint module. Let’s see how we can do this:

import pprint pprint.pprint(vars(Dog)) # Returns: # , '__doc__': None, '__init__': , '__module__': '__main__', '__weakref__': , 'birthday': , 'have_puppies': >

You’ve now learned how to print out all the attributes of a Python object in a more pretty format!

Conclusion

In this post, you learned how to print out the attributes of a Python object. You learned how to create a simple Python class and how to create an object. Then, you learned how to print out all the attributes of a Python object by using the dir() and vars() functions. Finally, you learned how to use the pprint module in order to print out the attributes in a prettier format.

To learn more about the dir() function, check out the official documentation here.

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