Extracting Data from an API using Python (requests)

Introduction
In today's data-driven world, APIs(Application Programming Interfaces) play a central role in allowing applications and services to interact and share information. Whether you are building a data dashboard, training machine learning models, or automating reporting process, chances are you will need to retrieve data from an API at some point.

This article provides a guide to extract data from an API using Python's requests library - a popular and de facto standard for making HTTP requests in python. We'll explore what APIs are, how HTTP requests work, and then walk through step-by-step process of sending a requests and handling the response.

What is an API?
An API acts as a bridge between two systems, allowing them to communicate. In the context of web APIs, it typically involves sending HTTP requests(like GET or POST) to a server and receiving responses in return. often in JSON format.
APIs are commonly used to:

• Fetch real-time data.

• Interact with third party platforms

• Perform actions remotely.

Getting Started With Python's Requests
Unlike most python's libraries, requests library is not included in python's standard library. Therefore, for you to use requests library, you have to install it so that you can use in your code. You can either install it into your virtual environment(good practice) or you can also install it into your global environment if you want to use it through multiple projects.

To install requests, run:

pip install requests

Once pip has finished the process of installing requests, then you cab use it in your application.

Step-by-Step Guide: Extracting Data from an API
After installing requests into your environment, let's walk through how to extract data from RESTful API using requests.

1.Choose an API to work With
Before you can start extracting data, you need to choose API that provides the kind of information you are looking for. APIs are available in almost every field. Some APIs are open and free to use i.e you can send a request and gat data without any setup.
Other APIs require you to register and use an API key - a unique code that identifies you and your usage. This helps the API provider manage traffic and prevent abuse.

2.Import the requests Library
The process begin by importing the required library:

import requests

1. Make a GET Request HTTP methods, e.g GET and POST, determine which actions you are trying to perform when making an HTTP request. One of the most common HTTP methods is GET. The GET method indicates that one is trying to get or retrieve data from a certain resource. To make a GET request using requests, you can invoke requests.get(). For example, we can make a GET request to JSONPlaceholder by calling get() with its URL as follows.

url = '(https://jsonplaceholder.typicode.com/posts)'
requests.get(url)

At this point you have made a request.

1. The Response A response is a powerful object that is used to inspect the results of the request made. Here were store the return value in a variable so that we can look at what we get.

url = '(https://jsonplaceholder.typicode.com/posts)'
response = requests.get(url)

At this point we have stored the value of our request in a variable called response. We will use response to see the results of our GET request.

5.Check the Response Status
The first set of information you can gather from response is the status code. A status code informs you of the status of the request.
For example, a 200 OK status means that your request was successful, while a 404 NOT FOUND status means that the resource you were looking for wasn't found. There are other codes that can be displaced.
This can be accessed by using .status_code:
response.status_code
Sometimes we can make this to be part of our code so that we can automatically know whether our request is successful or not.

if response.status_code == 200:
    print("Request was successful!")
else:
    print(f"Failed to retrieve data. Status code: {response.status_code}")

6.Parse the JSON Response

After the request is successful, we can convert the response to JSON format using .json(), so that we can use it in our python application. Most of the APIs return data in JSON format. This is a lightweight, human readable format that python can easily handle easily.
To parse the JSON response, we use .json() method as follows:

data = response.json()

This converts the json string into a python data structure - usually a dictionary or a list of dictionaries. From this point we can print the data to inspect and further deal with the data.

Conclusion
Working with APIs using Python's requests library opens the door to vast amounts of dynamic, real-time data. To summarize:

• Use requests.get() to fetch data from an API.

• Check the response status using .status_code.

• Parse the returned data using .json().