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In this tutorial, we will look at various ways to print class objects in Python. Suppose we want to print()print a class instance using the print("print") function, for example to see the data or value of an object. We can do this using the methods described below.

__repr__()Printing an object using the method in Python

__repr__()The method returns a printable representation of the object as a string. By default, it returns the name of the object's class and the object's address.

When we print()print an object in Python using print() function, the print( __str__()) method of the object is called. If it is not defined, then print() returns the return value of the print() method. That is why when we try to print an object of a user defined class using print() function, it returns the return value of the print() method.__str__()__repr__()print()__repr__()

Therefore, we can define or override __repr__()the method to print the summary or required value of an object.

Suppose we have a user defined class ClassAwhich has no __repr__()method. The following sample code demonstrates the output when we try to print an object __repr__()which has no method ClassA.

class classA:
    def __init__(self):
        self.var1 = 0
        self.var2 = "Hello"


A = classA()
print(A)

Output:

<__main__.classA object at 0x7fa29aa28c50>

Since we haven't defined __repr__()the method, by default it returns the name of the class and the address of the object.

Now, let's define the method classAof the class __repr__()and then use print()the function. print()and print(repr())should return the same value.

class classA:
    def __init__(self):
        self.var1 = 0
        self.var2 = "Hello"

    def __repr__(self):
        return "This is object of class A"


A = classA()
print(A)
print(repr(A))

Output:

This is object of class A
This is object of class A

__str__()Printing an object using the method in Python

__str__()The method returns a string version of the object in Python. If the object does not have __str__()a method, it returns __repr__()the same value as the method.

We see in the example code above that if __str__()the method is not defined, the print()method will use __repr__()the method to print a printable representation of the object.

Now, let's define the method ClassAof our example class __str__()and then try to print()print classAan object of using the function. print()The function should return __str__()the output of the method.

class classA:
    def __init__(self):
        self.var1 = 0
        self.var2 = "Hello"

    def __repr__(self):
        return "This is object of class A"

    def __str__(self):
        print("var1 =", self.var1)
        print("var2 =", end=" ")
        return self.var2


A = classA()
print(A)

Output:

var1 = 0
var2 = Hello

Printing objects in Python by adding new class methods

We can use another method to replace or define the __str__()and __repr__()methods of a class. We can describe a new print() method in a class which will print out the class attributes or values ​​of our choice.

The following example code demonstrates how to define and then use object.print()the method to print an object in Python.

class classA:
    def __init__(self):
        self.var1 = 0
        self.var2 = True
        self.var3 = "Hello"

    def print(self):
        print("var1 =", self.var1)
        print("var2 =", self.var2)
        print("var3 =", self.var3)


A = classA()
A.var2 = False
A.print()

Output:

var1 = 0
var2 = False
var3 = Hello