Basics of python Libraries

[shreyansh]

python libraries are collections of pre-written codes which you can reuse to do certain things instead of having to write everything from scratch. Here's the summary basics for Python libraries:

1. What is a Library?​

• A library, therefore, is a collection of modules. Modules are the Python files that provide a set of functions, classes, and methods to accomplish specific functionalities. Libraries facilitate the elimination of wrinkles from the coding process and increase its speed while limiting redundancy.

2. Built-in Libraries​

Python comes with many built-in libraries that provide a wide range of functionality. Some common ones include:

math: Provides mathematical functions.

import math
print(math.sqrt(16))  # Output: 4.0

random: For generating random numbers.

import random
print(random.randint(1, 10))  # Random integer between 1 and 10

datetime: For manipulating dates and times.

import datetime
now = datetime.datetime.now()
print(now)  # Current date and time

os: Provides functions for interacting with the operating system.

import os
print(os.getcwd())  # Get current working directory

sys: Provides access to some variables used or maintained by the interpreter.

import sys
print(sys.version)  # Python version

3. Third-Party Libraries​

Python has a rich ecosystem of third-party libraries available via the Python Package Index (PyPI). Some popular libraries include:

NumPy: For numerical computing and handling arrays.

import numpy as np
array = np.array([1, 2, 3])
print(array)

Pandas: For data manipulation and analysis, especially with tabular data.

import pandas as pd
df = pd.DataFrame({'A': [1, 2], 'B': [3, 4]})
print(df)

Matplotlib: For creating static, animated, and interactive visualizations.

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.show()

Requests: For making HTTP requests.

import requests
response = requests.get('https://api.github.com')
print(response.json())

4. Installing Libraries​

You can install third-party libraries using pip, the Python package installer. For example:

bash
pip install numpy

5. Importing Libraries​

You can import entire libraries or specific functions from them:

Importing an entire library:

import math

Importing specific functions:

from math import sqrt

6. Creating Your Own Library​

You can create your own library by organizing your functions and classes in a Python file (.py). This file can then be imported into other Python scripts.

7. Documentation and Help​

• Most libraries come with extensive documentation. You can access documentation online or use the built-in help() function in Python:

import math
help(math)

8. Best Practices​

• Use Virtual Environments: To manage dependencies for different projects, consider using virtual environments (e.g., venv or conda).
• Keep Libraries Updated: Regularly update your libraries to benefit from improvements and security fixes.

Conclusion​

Understanding Python libraries is important to smart programming and the proper leveraging of the vast ecosystem available. Libraries can help you do complex things with little code, so you are free to focus on solving problems rather than re-inventing the wheel.