Structure Keywords in Python : def, class, with, as, pass, lambda
Python def
def keyword is used to declare user defined functions.
def keyword in Python
The code defines a function named fun using the def keyword. When the function is called using fun(), it prints “Inside Function.” This code demonstrates the use of the def keyword to define and call a function in Python.
Python3
def fun(): print("Inside Function")fun() |
Inside Function
class in Python
class keyword is used to declare user defined classes.
Class Keyword in Python
This code defines a Python class named Dog with two class attributes, attr1 and attr2, and a method fun that prints these attributes. It creates an object Rodger from the Dog class, accesses the class attributes, and calls the method. When executed, it prints the values of attr1 and `attr2, and the method displays these values, resulting in the output shown.
Python3
class Dog: attr1 = "mammal" attr2 = "dog" def fun(self): print("I'm a", self.attr1) print("I'm a", self.attr2)Rodger = Dog()print(Rodger.attr1)Rodger.fun() |
mammal I'm a mammal I'm a dog
Note: For more information, refer to our Python Classes and Objects Tutorial .
With in Python
with keyword is used to wrap the execution of block of code within methods defined by context manager. This keyword is not used much in day to day programming.
With Keyword in Python
This code demonstrates how to use the with statement to open a file named 'file_path' in write mode ('w'). It writes the text 'hello world !' to the file and automatically handles the opening and closing of the file. The with statement is used for better resource management and ensures that the file is properly closed after the block is executed.
Python3
# using with statementwith open('file_path', 'w') as file: file.write('hello world !') |
as in Python
as keyword is used to create the alias for the module imported. i.e giving a new name to the imported module. E.g import math as mymath.
as Keyword In Python
This code uses the Python math module, which has been imported with the alias gfg. It calculates and prints the factorial of 5. The math.factorial() function is used to calculate the factorial of a number, and in this case, it calculates the factorial of 5, which is 120.
Python3
import math as gfgprint(gfg.factorial(5)) |
120
pass in Python
pass is the null statement in python. Nothing happens when this is encountered. This is used to prevent indentation errors and used as a placeholder.
Pass Keyword in Python
The code contains a for loop that iterates 10 times with a placeholder statement ‘pass', indicating no specific action is taken within the loop.
Python3
n = 10for i in range(n): # pass can be used as placeholder # when code is to added later pass |
Lambda in Python
Lambda keyword is used to make inline returning functions with no statements allowed internally.
Lambda Keyword in Python
The code defines a lambda function g that takes an argument x and returns x cubed. It then calls this lambda function with the argument 7 and prints the result. In this case, it calculates and prints the cube of 7, which is 343.
Python3
# Lambda keywordg = lambda x: x*x*xprint(g(7)) |
343
Python Keywords
Every language contains words and a set of rules that would make a sentence meaningful. Similarly, in Python programming language, there are a set of predefined words, called Keywords which along with Identifiers will form meaningful sentences when used together. Python keywords cannot be used as the names of variables, functions, and classes.
In this article, we will learn about Python keywords and how to use them to perform some tasks.