In the article on Modules in Python, we came across Python built-in modules that are pre-defined in Python library. In this article, let us discuss these built-in modules in detail.
Python has a large number of built-in modules. These modules can be used in Python programs by simply importing them using their name followed by the keyword 'import'. In Python, built-in modules are written in C and integrated with the Python interpreter.
Before understanding them in detail, let us see how they make coding much simpler.
Consider you need to find out whether the given two numbers are equal or not. To do this, assume you have written a module named ‘equal.py’ with the below-given function definition.
#function definition def equal(a, b):if(a == b): return True
Also, you have written a main() function in a separate file named 'main.py' with the below-given code.
#main function from equal import * a, b = 10, 10 print(equal(a, b))
When you execute the main function in the command prompt, you will get the output shown below.
In Python, each and every built-in module has a large number of predefined functions to perform specific tasks. For instance, Python has a built-in module named 'operator', inside which the function called 'eq()' is defined. This function returns the boolean value of 'True' if the given two input values are equal. Else, returns False.
So now, we can make use of this operator module in our main() program to check if two numbers are equal. This means we would no longer need that 'equal.py' module.
#main function from operator import * a, b = 10, 10 print(eq(a, b))
Next, let us discuss some of the Python built-in modules in detail.
Using Python built-in function help(), we can obtain the list of built-in modules available in Python. On executing the line help ('modules') in Python IDE, you can see all the Python built-in modules. Some of the frequently used ones are discussed below.
Next, let us see how to implement these built-in modules in the Python programs.
from operator import * a, b = 10, 20 #prints the product of the values 'a' and 'b' print(mul(a, b)) #prints True if the value of 'a' is greater than 'b'. Else, False print(gt(a, b)) #prints the remainder value, when the value of 'a' is divided by 'b' print(mod(a, b)) #concatenates and prints the given two strings print(concat("FACE", "Prep"))
Output: 200 False 10 FACEPrep
from decimal import * a, b = 10, 3 c = a / b print(c) print(Decimal(c)) #prints the complete decimal value of c
Output: 3.3333333333333335 3.333333333333333481363069950020872056484222412109375
c) Example Using Random Module
from random import * print(randint(10, 20)) #prints a random number between the given range list1 = [30, 23, 45, 16, 89, 56] print(choice(list1)) #prints a random element from the given iterator print(uniform(10, 20)) #prints a random float number between two given values
Output: 18 16 12.908184799437432
d) Example Using String Module
from string import * print(capwords("fACE prep")) #capitalizes the first letter of each words print(ascii_letters) #prints all lowercase and uppercase letters
Output: FACE Prep abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
e) Example Using Math Module
from math import * print(sqrt(16)) #prints the square root of the value 16 in the form of a floating-point value print(factorial(5)) #prints the factorial of the value 5
Output: 4.0 120
Since Python provides a lot of built-in modules, it is advisable to use built-in modules rather than user-created modules to perform basic operations.