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 :

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

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

Output :

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

#Save this code in a file named, about_us.py person1 = { "name": "AyaN", "age": 24, "country": "IND" } person2 = { "name": "Apu", "age": 22, "country": "IND" } person3 = { "name": "Dev", "age": 21, "country": "IND" } person4 = { "name": "Symul", "age": 20, "country": "BD" }

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

#Save this code in a file named, my_file.py import about_us val1 = about_us.person1["name"] print("Person1 name : ",val1) val2 = about_us.person2["age"] print("\nPerson2 age : ",val2) val3 = about_us.person2["country"] print("Person2 country : ",val3) val4 = about_us.person4["name"] print("\nPerson4 name : ",val4) val5 = about_us.person4["age"] print("Person4 age : ",val5) val6 = about_us.person4["country"] print("Person4 country : ",val6) input()

Output :

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 :

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

Output :

Built-in Modules :

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

Example :

import platform x = platform.system() y = platform.release() print("System Platfrom Name : ",x) print("System Release/OS Version : ",y) input()

Output :

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 :

#List all the defined names belonging to the platform module import platform x = dir(platform) print(x) input()

Output :

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