Python getattr() function is used to access the attribute value of an object and also gives an option of executing the default value in case of unavailability of the key.
Python getattr() Method Syntax
Syntax : getattr(obj, key, def)
Parameters:
- obj : The object whose attributes need to be processed.
- key : The attribute of object
- def : The default value that need to be printed in case attribute is not found.
Returns : Object value if value is available, default value in case attribute is not present and returns AttributeError in case attribute is not present and default value is not
specified.
Example
In the given example, getattr() is used to access both attributes and methods of an object dynamically. It provides flexibility in working with objects whose attributes or methods are not known in advance.
Python3
class Calculator: def add(self, a, b): return a + bcalc = Calculator()# Accessing a method dynamicallyoperation = getattr(calc, "add")result = operation(3, 5)print(result) |
Output :
8
How getattr() works in Python?
The getattr() function in Python is a built-in function that allows you to dynamically access an object’s attributes or methods by name. To understand how getattr() works in Python, we have created a class named GFG with two class attributes name, and age. Further, we are creating two attribute names and ages. Then we created an object of the class and we are getting the attribute name-value with getattr().
Python3
class GfG: name = "Lazyroar" age = 24obj = GfG()print("The name is " + getattr(obj, 'name')) |
Output:
The name is Lazyroar
getattr() in Python Examples
getattr() when the Named Attribute is not Found
In this example, we have defined a class name GFG and there are two class variables named, the age we call the gender attribute which is not present in the class, which is showing the output AttributeError.
Python3
# Python code to demonstrate# working of getattr()# declaring classclass GfG: name = "Lazyroar" age = 24# initializing objectobj = GfG()# use of getattr without defaultprint("Gender is " + getattr(obj, 'gender')) |
Output:
AttributeError: 'GfG' object has no attribute 'gender'
Performance Analysis and getattr Python with Parameter
In this example, we are using the time class to show that getattr() takes more time rather than the conventional method in Python.
Python3
# Python code to demonstrate# performance analysis of getattr()import time# declaring classclass GfG: name = "Lazyroar" age = 24# initializing objectobj = GfG()# use of getattr to print namestart_getattr = time.time()print("The name is " + getattr(obj, 'name'))print("Time to execute getattr " + str(time.time() - start_getattr))# use of conventional method to print namestart_obj = time.time()print("The name is " + obj.name)print("Time to execute conventional method " + str(time.time() - start_obj)) |
Output:
The name is Lazyroar
Time to execute getattr 5.0067901611328125e-06
The name is Lazyroar
Time to execute conventional method 1.1920928955078125e-06
Python getattr() function Call
In this example, we have created a GFG class and a call function. We have created an object of GFG class and we have called the getarr() in Python with the object, function, and parameter.
Python3
# Python code to demonstrate# working of getattr()# declaring classclass GfG: def __init__(self, name, age): self.name = name self.age = age def call(self, x): print(f"{self.name} called with parameters '{x}'") return# initializing objectobj = GfG("Vivek", 10)print(obj)print(GfG)print(getattr(obj,'call'))getattr(obj,'call')('arg') |
Output:
<__main__.GfG object at 0x0000023C1ED92748>
<class '__main__.GfG'>
<bound method GfG.call of <__main__.GfG object at 0x0000023C1ED92748>>
Vivek called with parameters 'arg'
Applications of getattr() in Python
The getattr() function in Python is commonly used in various applications and scenarios. Such as:
- Accessing attributes dynamically
- Handling optional attributes
- Configuring objects
- API integration
