Skip to content
Related Articles

Related Articles

Basics Of Python Modules
  • Last Updated : 28 Jul, 2020

A library refers to a collection of modules that together cater to a specific type of needs or application. Module is a file(.py file) containing variables, class definitions statements, and functions related to a particular task. Python modules that come preloaded with Python are called standard library modules.

Creating our module

We will be creating a module named tempConversion.py that converts values from F to C and vice-versa.




# tempConversion.py to convert between
# between Fahrenheit and Centigrade
  
# function to convert F to C
def to_centigrade(x):
      return 5 * (x - 32) / 9.0
  
# function to convert C to F
def to_fahrenheit(x):
       return 9 * x / 5.0 + 32
  
# constants
  
# water freezing temperature(in Celcius)
FREEZING_C = 0.0  
  
# water freezing temperature(in Fahrenheit)     
FREEZING_F = 32.0      

Now save this python file and the module is created. This module can be used in other programs after importing it.

Importing a module

In python, in order to use a module, it has to be imported. Python provides multiple ways to import modules in a program :

  1. To import the entire module :
    import module_name
  2. To import only a certain portion of the module :
    from module_name import object_name
  3. To import all the objects of the module :
    from module_name import *

Using an imported module

After importing the module, we can use any function/definition of the imported module as per the following syntax:



module_name.function_name() 

This way of referring to the module’s object is called dot notation.
If we import a function using from, there is no need to mention the module name and the dot notation to use that function.

Example 1 : Importing the whole module :




# importing the module
import tempConversion
  
# using a function of the module
print(tempConversion.to_centigrade(12))
  
# fetching an object of the module
print(tempConversion.FREEZING_F)

Output :

-11.11111111111111
32.0

Example 2 : Importing particular components of the module :




# importing the to_fahrenheit() method
from tempConversion import to_fahrenheit
  
# using the imported method
print(to_fahrenheit(20))
  
# importing the FREEZING_C object
from tempConversion import FREEZING_C
  
# printing the imported variable
print(FREEZING_C)

Output :

68.0
0.0

Python standard library functions

The python interpreter has a number of functions built into it that are always available. To use these built-in functions of python directly call the functions, like function_name(). Some built-in library functions are : input(), int(), float() etc




num = 5
print("Number entered = ", num)
  
# oct() converts to octal number-string
onum = oct(num)   
  
# hex() coverts to hexadecimal number-string     
hnum = hex(num)     
     
print("Octal conversion yields", onum)
print("Hexadecimal conversion yields", hnum)
print(num)

Output :

Number entered = 5
Octal conversion yields 0o5
Hexadecimal conversion yields 0x5
5

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.

My Personal Notes arrow_drop_up
Recommended Articles
Page :