What are libraries in Python? And how to use them?

What are libraries in Python?
Libraries in Python are collections of pre-written code that you can use in your own programs. These libraries can contain functions, classes, and variables that you can use to perform a variety of tasks, such as connecting to a database, reading and writing files, or performing mathematical calculations.

Using libraries in Python is a convenient way to avoid writing code from scratch and can save you a lot of time and effort.

How to import a library in Python
To use a library in Python, you need to import it first. You can do this using the import statement. For example, to import the math library, you would write the following code:

import math

This will allow you to use the functions and variables in the math library in your code.

You can also import specific functions or variables from a library using the from keyword. For example, to import the sqrt function from the math library, you can write the following code:

from math import sqrt

You can also import multiple functions or variables at once by separating them with commas. For example:

from math import sqrt, sin, cos

How to use a library in Python

Once you have imported a library, you can use its functions and variables by referencing the library name followed by a dot and the function or variable name.

For example, to use the sqrt function from the math library, you would write the following code:

import math

result = math.sqrt(9)
print(result) # Output: 3.0

Or, if you imported the sqrt function directly:

from math import sqrt

result = sqrt(9)
print(result) # Output: 3.0
You can also use variables from a library in the same way. For example, the math library contains a variable called pi that represents the value of pi:

import math

result = math.pi
print(result) # Output: 3.141592653589793

Conclusion

Libraries are a convenient way to use pre-written code in your own Python programs. You can import entire libraries or specific functions and variables from them using the import statement. Once you have imported a library, you can use its functions and variables by referencing the library name followed by a dot and the function or variable name.