Harness the Power of APIs with Python: A Step-by-Step Guide for Beginners

APIs (Application Programming Interfaces) are powerful tools that allow programs you create to interact with external services, which can significantly enhance their usability without requiring a lot of work. We see it being used a lot with ChatGPT, and a great way to learn how to start using an API is with Python.

What is an API?

An API, or Application Programming Interface, defines the methods and data formats that applications can use to request and exchange information with another application.

Components of an API

Endpoints

Endpoints are URLs provided by the API through which you can access its functionality, and each will have a different function.

Requests and Responses

A request is when you send a request to an endpoint, which can include parameters and data. The response is what you get back, and it will usually be in an XML or JSON format.

Methods

Methods are what you use for requests using an API and can include GET, POST, PUT, and DELETE.

Authentication

Most APIs require you to sign up to ensure that only authorized users can access the data. After you sign up, you will receive a key that you add to your programming code to access the data.

Rate Limiting

To prevent abuse, APIs often have rate limits, restricting the number of requests a user can make within a certain period, especially for free APIs, and exceeding this limit can result in additional fees.

How Can I Use an API?

To demonstrate how to use an API, we are going to create a small Python script to access the REST Countries API, which doesn’t require a key or a subscription, so that everyone can give it a try. We’ll break down and explain the code first, then provide the complete code you can copy and paste.

This guide assumes you already have Python installed and know how to use the scripts. Check out our Getting Started with Python guide if you are a beginner.

Setting Up the Environment

Before we can get started writing the script, you’ll need to install the requests library from the command prompt if you don’t already have it.

pip install requests

Fetching Data from the API

The first thing we will do is write a function to fetch the available data from the API. We’ll use a get request, and if successful, the API will return a JSON response.

import requests

# Function to fetch data from the REST Countries API

def fetch_country_data():

url = "https://restcountries.com/v3.1/all"

response = requests.get(url)

if response.status_code == 200:

return response.json()

else:

return None

Getting Country Information

Next, we’ll create a Python function to sort through the data to extract information about a country based on the user’s input.

# Function to get country information

def get_country_info(country_name, country_data):

for country in country_data:

if country_name.lower() in (country['name']['common'].lower(), country['name']['official'].lower()):

return {

'Name': country['name']['common'],

'Official Name': country['name']['official'],

'Population': country['population'],

'Capital': country.get('capital', ['N/A'])[0],

'Region': country['region'],

'Subregion': country.get('subregion', 'N/A'),

'Languages': ', '.join(country.get('languages', {}).values()),

'Currencies': ', '.join([currency['name'] for currency in country.get('currencies', {}).values()]),

'Flag URL': country['flags']['png']

}

return None

Displaying Country Information

Next, we need a function that displays the information we need on screen.

# Function to display country information

def display_country_info(country_info):

if country_info:

print("\nCountry Information:")

for key, value in country_info.items():

print(f"{key}: {value}")

else:

print("Country not found.")

Main Program Loop

Finally, we’ll need the main function that will continuously prompt the user for a country name and display the information until the user decides to exit.

# Main program

def main():

print("Welcome to the Country Information Program!")

country_data = fetch_country_data()

if not country_data:

print("Error fetching data from the API.")

return

while True:

country_name = input("\nEnter the name of the country (or type 'exit' to quit): ").strip()

if country_name.lower() == 'exit':

break

country_info = get_country_info(country_name, country_data)

display_country_info(country_info)

print("Thank you for using the Country Information Program!")

if __name__ == "__main__":

main()

Complete Code

import requests

# Main program

def main():

print("Welcome to the Country Information Program!")

country_data = fetch_country_data()

if not country_data:

print("Error fetching data from the API.")

return

while True:

country_name = input("\nEnter the name of the country (or type 'exit' to quit): ").strip()

if country_name.lower() == 'exit':

break

country_info = get_country_info(country_name, country_data)

display_country_info(country_info)

print("Thank you for using the Country Information Program!")

if __name__ == "__main__":

main()

What's Next?

This code only demonstrates a sample of what the REST Countries API offers. To help you understand the code better, try to modify it to use some of the other available data.

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