The Python installers for the Windows platform usually include the [entire standard library](https://docs.python.org/3/library/index.html) and often also include many additional components.
Bulit in modules which will be covered in this documentaion are
- math - for mathematical functions
- random - to generate pseudo-random numbers
- sys - system specific parameters and functions
- os - operating system interfaces
In addition to the standard library, there is a growing collection of several thousand components (from individual programs and modules to packages and entire application development frameworks), available from PyPI , which you are free to explore after getting comfortable using some of the built in modules .
We can import modules which are available under standard library by using from , as and import keyword .
import module_name # imports all the functions of math library
import module_name as short_name # same as above but shorting the name math to mtImporting specific fuctions from modules . For example ,
from math import sqrt # importing square root function from math library
from math import log # importing log function
from math import * # import all function from math libraryThis module is used to access to the mathematical functions defined under standard library .
import math
print(math.sqrt(16)) # >>> 4.0
print(math.factorial(4)) # >>> 24
# parameters (x,base)
print(math.log(8,2)) # >>> 3.0
# parameters (element)
print(math.log2(8)) # >>> 3.0
# math.radians(x) converts x into radians and math.sin gives sin of math.randian(x) radians .
print(math.sin(math.radians(90))) # >>> 1.0This module implements pseudo-random number generators for various distributions.
from random import *
# we don't have to do random.uniform(x,y) anymore . prints random floating x such that 1.5<= x <5.5
print(uniform( 1.5, 5.5)) # >>> 5.139972864965343
#prints random floating x such that 0.0<= x <1.0
print(random()) # >>> 0.5898863000736234
# prints random integer x , where 0<=x <10
print(randrange(10)) # >>> 4
# prints random integer x , where a<=x <b
print(randrange(2,10)) # >>> 5
# Single random element from a sequence
print(choice(['win', 'lose', 'draw'])) # >>>'draw'
languages = ["scala","bf","c++","java"]
# Shuffle a list
shuffle(languages)
print(languages) # >>> ['bf', 'c++', 'java', 'scala']
# Four samples without replacement
print(sample([10, 20, 30, 40, 50], k=4)) # >>> [30, 40, 20, 50]This module provides access to some variables used or maintained by the interpreter and to functions that interact strongly with the interpreter. It is always available.
This module provides a portable way of using operating system dependent functionality.
import os
#changes current working directory to test directory inside current directory
os.chdir("./test")
os.getlogin() # >>> 'Nishchith'
# path of current working directory
os.getcwd() # >>> './GitHub/intro-to-programming'