Introduction to APIs

Acquisizione dati semplificata con pandas

Amany Mahfouz

Instructor

Application Programming Interfaces

Defines how a application communicates with other programs
Way to get data from an application without knowing database details

A form with some entries checked and some blank

Application Programming Interfaces

Defines how a application communicates with other programs
Way to get data from an application without knowing database details

A form and a storefront. An arrow indicates that the form is being sent to the store.

Application Programming Interfaces

Defines how a application communicates with other programs
Way to get data from an application without knowing database details

An open package and a storefront. The package is in the place the order form used to be. An arrow indicates that the store has sent the package.

Requests

Send and get data from websites
Not tied to a particular API
requests.get() to get data from a URL

requests.get()

requests.get(url_string) to get data from a URL
Keyword arguments
- params keyword: takes a dictionary of parameters and values to customize API request
- headers keyword: takes a dictionary, can be used to provide user authentication to API
Result: a response object, containing data and metadata
- response.json() will return just the JSON data

response.json() and pandas

response.json() returns a dictionary
read_json() expects strings, not dictionaries
Load the response JSON to a dataframe with pd.DataFrame()
- read_json() will give an error!

Yelp Business Search API

Yelp logo

Yelp Business Search API

Yelp Business Search API documentation. Request endpoint and some parameters are shown.

Yelp Business Search API

Yelp Business Search API documentation. API endpoint URL is highlighted.

Yelp Business Search API

Yelp Business Search API documentation. An optional term parameter is highlighted.

Yelp Business Search API

Yelp Business Search API documentation. Required locational parameters are highlighted.

Yelp Business Search API

Yelp Business Search API documentation, showing an example response JSON

Making Requests

import requests
import pandas as pd


api_url = "https://api.yelp.com/v3/businesses/search"

# Set up parameter dictionary according to documentation
params = {"term": "bookstore", 
         "location": "San Francisco"}

# Set up header dictionary w/ API key according to documentation
headers = {"Authorization": "Bearer {}".format(api_key)}


# Call the API
response = requests.get(api_url, 
                        params=params, 
                        headers=headers)

Parsing Responses

# Isolate the JSON data from the response object
data = response.json()
print(data)

{'businesses': [{'id': '_rbF2ooLcMRA7Kh8neIr4g', 'alias': 'city-lights-bookstore-san-francisco', 'name': 'City Lights Bookstore', 'image_url': 'https://s3-media1.fl.yelpcdn.com/bphoto/VRydkkpVbA3CeVLBKzs2Vw/o.jpg', 'is_closed': False,

# Load businesses data to a dataframe
bookstores = pd.DataFrame(data["businesses"])
print(bookstores.head(2))

                                  alias        ...                                                    url
0   city-lights-bookstore-san-francisco        ...      https://www.yelp.com/biz/city-lights-bookstore...
1  alexander-book-company-san-francisco        ...      https://www.yelp.com/biz/alexander-book-compan...

[2 rows x 16 columns]

Let's practice!

Acquisizione dati semplificata con pandas