Python Modules

Difficulty Level : Easy
Last Updated : 21 Jan, 2022

A Python module is a file containing Python definitions and statements. A module can define functions, classes, and variables. A module can also include runnable code. Grouping related code into a module makes the code easier to understand and use. It also makes the code logically organized.

Example: create a simple module

Python3

# A simple module, calc.py
 
def add(x, y):
    return (x+y)
 
def subtract(x, y):
    return (x-y)

Import Module in Python – Import statement

We can import the functions, classes defined in a module to another module using the import statement in some other Python source file.

Syntax:

import module

When the interpreter encounters an import statement, it imports the module if the module is present in the search path. A search path is a list of directories that the interpreter searches for importing a module. For example, to import the module calc.py, we need to put the following command at the top of the script.

Note: This does not import the functions or classes directly instead imports the module only. To access the functions inside the module the dot(.) operator is used.

Example: Importing modules in Python

Python3

# importing  module calc.py
import calc
 
print(calc.add(10, 2))

Output:

The from import Statement

Python’s from statement lets you import specific attributes from a module without importing the module as a whole.

Example: Importing specific attributes from the module

Python3

# importing sqrt() and factorial from the
# module math
from math import sqrt, factorial
 
# if we simply do "import math", then
# math.sqrt(16) and math.factorial()
# are required.
print(sqrt(16))
print(factorial(6))

Output:

4.0
720

Import all Names – From import * Statement

The * symbol used with the from import statement is used to import all the names from a module to a current namespace.

Syntax:

from module_name import *

The use of * has its advantages and disadvantages. If you know exactly what you will be needing from the module, it is not recommended to use *, else do so.

Example: Importing all names

Python3

# importing sqrt() and factorial from the
# module math
from math import *
 
# if we simply do "import math", then
# math.sqrt(16) and math.factorial()
# are required.
print(sqrt(16))
print(factorial(6))

Output

4.0
720

Locating Modules

Whenever a module is imported in Python the interpreter looks for several locations. First, it will check for the built-in module, if not found then it looks for a list of directories defined in the sys.path. Python interpreter searches for the module in the following manner –

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

Python3

# importing sys module
import sys
 
# importing sys.path
print(sys.path)

Output:

[‘/home/nikhil/Desktop/gfg’, ‘/usr/lib/python38.zip’, ‘/usr/lib/python3.8’, ‘/usr/lib/python3.8/lib-dynload’, ”, ‘/home/nikhil/.local/lib/python3.8/site-packages’, ‘/usr/local/lib/python3.8/dist-packages’, ‘/usr/lib/python3/dist-packages’, ‘/usr/local/lib/python3.8/dist-packages/IPython/extensions’, ‘/home/nikhil/.ipython’]

Importing and renaming module

We can rename the module while importing it using the as keyword.

Example: Renaming the module

Python3

# importing sqrt() and factorial from the
# module math
import math as gfg
 
# if we simply do "import math", then
# math.sqrt(16) and math.factorial()
# are required.
print(gfg.sqrt(16))
print(gfg.factorial(6))

Output

4.0
720

The dir() function

The dir() built-in function returns a sorted list of strings containing the names defined by a module. The list contains the names of all the modules, variables, and functions that are defined in a module.

Python3

#  Import built-in module  random
import  random
print(dir(random))

Output:

[‘BPF’, ‘LOG4’, ‘NV_MAGICCONST’, ‘RECIP_BPF’, ‘Random’, ‘SG_MAGICCONST’, ‘SystemRandom’, ‘TWOPI’, ‘_BuiltinMethodType’, ‘_MethodType’, ‘_Sequence’, ‘_Set’, ‘__all__’, ‘__builtins__’, ‘__cached__’, ‘__doc__’, ‘__file__’, ‘__loader__’, ‘__name__’, ‘__package__’, ‘__spec__’, ‘_acos’, ‘_bisect’, ‘_ceil’, ‘_cos’, ‘_e’, ‘_exp’, ‘_inst’, ‘_itertools’, ‘_log’, ‘_pi’, ‘_random’, ‘_sha512’, ‘_sin’, ‘_sqrt’, ‘_test’, ‘_test_generator’, ‘_urandom’, ‘_warn’, ‘betavariate’, ‘choice’, ‘choices’, ‘expovariate’, ‘gammavariate’, ‘gauss’, ‘getrandbits’, ‘getstate’, ‘lognormvariate’, ‘normalvariate’, ‘paretovariate’, ‘randint’, ‘random’, ‘randrange’, ‘sample’, ‘seed’, ‘setstate’, ‘shuffle’, ‘triangular’, ‘uniform’, ‘vonmisesvariate’, ‘weibullvariate’]

Code Snippet illustrating python built-in modules:

Python3

# importing built-in module math
import math
 
# using square root(sqrt) function contained
# in math module
print(math.sqrt(25))
 
# using pi function contained in math module
print(math.pi)
 
# 2 radians = 114.59 degrees
print(math.degrees(2)) 
 
# 60 degrees = 1.04 radians
print(math.radians(60)) 
 
# Sine of 2 radians
print(math.sin(2)) 
 
# Cosine of 0.5 radians
print(math.cos(0.5)) 
 
# Tangent of 0.23 radians
print(math.tan(0.23))
 
# 1 * 2 * 3 * 4 = 24
print(math.factorial(4)) 
 
# importing built in module random
import random
 
# printing random integer between 0 and 5
print(random.randint(0, 5)) 
 
# print random floating point number between 0 and 1
print(random.random()) 
 
# random number between 0 and 100
print(random.random() * 100) 
 
List = [1, 4, True, 800, "python", 27, "hello"]
 
# using choice function in random module for choosing
# a random element from a set such as a list
print(random.choice(List))
 
 
# importing built in module datetime
import datetime
from datetime import date
import time
 
# Returns the number of seconds since the
# Unix Epoch, January 1st 1970
print(time.time()) 
 
# Converts a number of seconds to a date object
print(date.fromtimestamp(454554)) 

Output:

5.0
3.14159265359
114.591559026
1.0471975512
0.909297426826
0.87758256189
0.234143362351
24
3
0.401533172951
88.4917616788
True
1461425771.87
1970-01-06

This article is contributed by Gaurav Shrestha. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. If you like GeeksforGeeks and would like to contribute, you can also write an article and mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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Related Articles

Table of Contents

Python Modules

Example: create a simple module

Python3

Import Module in Python – Import statement

Example: Importing modules in Python

Python3

The from import Statement

Example: Importing specific attributes from the module

Python3

Import all Names – From import * Statement

Example: Importing all names

Python3

Locating Modules

Example: Directories List for Modules

Python3

Importing and renaming module

Example: Renaming the module

Python3

The dir() function

Python3

Python3

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