Python Modules
In Python, a module is a file with Python code. This Python file may contain function definitions, variables, classes, and executable statements that can be included in the application.
Create a Module
A module is usually created to split a longer program into several files for easier maintenance.
To create a module, simply create and save a Python file with .py file extension.
Example
my_module.py
def add(a, b):
result = a + b
return result
def substract(a, b):
result = a - b
return result
Use the Module
To use any function from a module, you simply need to import the module in your code by using the import statement followed by the module name.
Example
import my_module
x = my_module.add(10, 40)
y = my_module.substract(10, 5)
print(x)
print(y)
Module Naming Convention
A module file name can be anything but must have .py file extension. A module file name must start with a small letter and if you want to use multiple words then each word should be separated by _ underscore.
Module Alias Name
You can call your module with a different name by using the as keyword while importing the module.
Example
import my_module as md
x = md.add(10, 40)
y = md.substract(10, 5)
print(x)
print(y)
Import From Module
You can import only some functions, classes, or variables from a module instead of importing the entire module by using the from keyword.
Example
import add from my_module
x = add(10, 40)
print(x)
You can also import multiple parts from a module separated by , comma.
Example
import add, substract from my_module
x = add(10, 40)
y = substract(10, 5)
print(x)
print(y)
Built-in Modules
There are several built-in modules in Python that you can use anywhere in your code.
dir() Function in Python
The dir() function is a built-in function in Python that returns a list of function names and attribute names of the object it is called upon.
Example
import my_module
x = dir(my_module)
print(x)
len() Function in Python
The len() function is a built-in function in Python that returns the length of a string, array, tuple, list, dictionary, etc.
Example
x = "Hello Buddy"
y = [11,23,54,74,54]
x_length = len(x)
y_length = len(y)
print(x)
print(y)