Python Modules
Table Of Contents:
- What Is A Python Module?
- Creating A Python Module.
- Importing Python Module.
- The dir() Function.
- Import Using From Keyword.
- Import Module Using *.
- Locating Your Module.
- Renaming Your Module.
(1) What Is A Python Module?
- If you want to make package of your code functionality and make it available to others , then you can use the concept of python module.
- A module can define functions, classes, and variables inside it.
- It can also include executable code in itself.
- Grouping related code into a module makes the code easier to understand and use.
- A Module makes code logically organized.
(2) Creating A Python Module?
- A python module is simply just a .py file which contains logically related python code.
- let us create a calculator python file which will do all mathematical operations.
- Like addition, subtraction, multiplication and division.
Example
Calculator.py
def add(x,y):
return x+y
def substract(x,y):
return x-y
def multiply(x,y):
return x*y
def divide(x,y):
return x/y
Note:
- I have created Calculator.py python module and saved it on my local drive.
- You can call this as Calculator module.
(3) Importing Python Module?
- As of now we have created a python module called Calculator.py .
- Now it’s time to use our module.
- We can use “import” keyword to import a python module.
- Put your Calculator.py in the same folder where you are running the import statement.
Example
import Calculator
print('Sum:',Calculator.add(10,30))
print('Substract:',Calculator.substract(10,30))
print('Multiply:',Calculator.multiply(10,30))
print('Divide:',Calculator.divide(10,30))
Output:
Sum: 40
Substract: -20
Multiply: 300
Divide: 0.3333333333333333
Note:
- To call the method inside the Calculator module, we have to use module name dot the method name.
- Like Calculator.add(10,20) .
(4) The dir() Function?
- To know what are the methods present inside your module you can use the dir() method.
- It will list out all the methods and variables inside the module.
Example
import Calculator
dir(Calculator)
Output:
['__builtins__',
'__cached__',
'__doc__',
'__file__',
'__loader__',
'__name__',
'__package__',
'__spec__',
'add',
'divide',
'multiply',
'substract']
(5) Import Using From Keyword.
- If you want to import some specific methods from your module then you can use from statement.
- from statement will import a specified item from module not all the items.
Example-1
from Calculator import add
print(add(20,40))
Output:
60
Example-2
from Calculator import multiply
print(multiply(20,40))
Output:
800
(6) Import Module Using *
- If you want to import all the methods present inside the module at a time, then you can use ( * ).
- It will include all the methods into your file.
Example-1
from Calculator import *
print('Sum:',add(10,30))
print('Substract:',substract(10,30))
print('Multiply:',multiply(10,30))
print('Divide:',divide(10,30))
Output:
Sum: 40
Substract: -20
Multiply: 300
Divide: 0.3333333333333333
Note:
- Here you can use all the methods present inside Calculator module by there name.
- I can call the function directly by there name in my code.
(7) Renaming Your Module
- If you want to give some short name to your module than you can do that.
- By using “as” keyword you can give some short name to your module which will be handy to use.
Example-1
import Calculator as cl
print('Sum:',cl.add(10,30))
print('Substract:',cl.substract(10,30))
print('Multiply:',cl.multiply(10,30))
print('Divide:',cl.divide(10,30))
Output:
Sum: 40
Substract: -20
Multiply: 300
Divide: 0.3333333333333333
Note:
- Here I have renamed the Calculator module as cl.
- I can call the methods inside it using cl.add(10,20).
(8) Locating Your Module
- When you are importing a module, python interpreter looks for several locations where it may present.
- First, it searches for the module in the current directory.
- If the module isn’t found in the current directory, Python then searches each directory in the shell variable PYTHONPATH. The PYTHONPATH is an environment variable, consisting of a list of directories.
- If that also fails python checks the installation-dependent list of directories configured at the time Python is installed.
Example- Directories List for Modules
# importing sys module
import sys
# importing sys.path
print(sys.path)
Output:
['C:\\Users\\SuSahoo\\Blogs', 'C:\\Users\\SuSahoo\\Anaconda3\\python39.zip',
'C:\\Users\\SuSahoo\\Anaconda3\\DLLs', 'C:\\Users\\SuSahoo\\Anaconda3\\lib',
'C:\\Users\\SuSahoo\\Anaconda3', '', 'C:\\Users\\SuSahoo\\Anaconda3\\lib\\site-packages',
'C:\\Users\\SuSahoo\\Anaconda3\\lib\\site-packages\\win32',
'C:\\Users\\SuSahoo\\Anaconda3\\lib\\site-packages\\win32\\lib',
'C:\\Users\\SuSahoo\\Anaconda3\\lib\\site-packages\\Pythonwin']