Python Modules:

What is a Module ?

A module allows you to logically organize your Python code. Grouping related code into a module makes the code easier to understand and use. A module is a Python object with arbitrarily named attributes that you can bind and reference.

Simply, a module is a file consisting of Python code. A module can define functions, classes and variables. A module can also include runnable code.

Example :

The Python code for a module named aname normally resides in a file named aname.py. Here's an example of a simple module, Hello.py :

  1. #Save this code in a file named, Hello.py
  2. def name_func( name ):
  3. print ("Hello, ", name,":)")
  4. return

The import Statement :

You can use any Python source file as a module by executing an import statement in some other Python source file. The import has the following syntax :
import module1[, module2[,... moduleN]

Example :

  1. #Save this code in a file named, my_file.py
  2. #Import module Hello
  3. import Hello
  4. #Now you can call defined function that module as follows
  5. Hello.name_func("AyaN")
  6. input()

Output :

python modules examples

Variables in Module :

The module can contain functions, as already described, but also variables of all types (arrays, dictionaries, objects etc) :

Example :

Save this code in a file named, about_us.py

  1. #Save this code in a file named, about_us.py
  2. person1 = {
  3. "name": "AyaN",
  4. "age": 24,
  5. "country": "IND"
  6. }
  7. person2 = {
  8. "name": "Apu",
  9. "age": 22,
  10. "country": "IND"
  11. }
  12. person3 = {
  13. "name": "Dev",
  14. "age": 21,
  15. "country": "IND"
  16. }
  17. person4 = {
  18. "name": "Symul",
  19. "age": 20,
  20. "country": "BD"
  21. }

Save this code in a file named, my_file.py and Import the module named about_us .

  1. #Save this code in a file named, my_file.py
  2. import about_us
  3. val1 = about_us.person1["name"]
  4. print("Person1 name : ",val1)
  5. val2 = about_us.person2["age"]
  6. print("\nPerson2 age : ",val2)
  7. val3 = about_us.person2["country"]
  8. print("Person2 country : ",val3)
  9. val4 = about_us.person4["name"]
  10. print("\nPerson4 name : ",val4)
  11. val5 = about_us.person4["age"]
  12. print("Person4 age : ",val5)
  13. val6 = about_us.person4["country"]
  14. print("Person4 country : ",val6)
  15. input()

Output :

python module variables access

Naming a Module :

You can name the module file whatever you like, but it must have the file extension .py (example : Hello.py, about_us.py etc.)

Re-naming a Module :

You can create an alias when you import a module, by using the as keyword. Example :

Example :

  1. #Create an alias for about_us called abts
  2. import about_us as abts
  3. val1 = abts.person3["name"]
  4. print("Person3 name : ",val1)
  5. val2 = abts.person3["age"]
  6. print("Person2 age : ",val2)
  7. input()

Output :

python modules remane

Built-in Modules :

There are several built-in modules in Python, which you can import whenever you like.

Example :

  1. import platform
  2. x = platform.system()
  3. y = platform.release()
  4. print("System Platfrom Name : ",x)
  5. print("System Release/OS Version : ",y)
  6. input()

Output :

built-in modules in python

Using the dir() Function :

There is a built-in function to list all the function names (or variable names) in a module. The dir() function.

Example :

  1. #List all the defined names belonging to the platform module
  2. import platform
  3. x = dir(platform)
  4. print(x)
  5. input()

Output :

python the dir() function

Note : The dir() function can be used on all modules, also the ones you create yourself.


Computer Science Engineering

Special Notes

It's a special area where you can find special questions and answers for CSE students or IT professionals. Also, In this section, we try to explain a topic in a very deep way.

CSE Notes