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Python Set Operations Explained: From Theory to Real-Time Applications

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A  set  in Python is an unordered collection of unique elements. It is useful when storing distinct values and performing operations like union, intersection, or difference. Real-Time Example: Removing Duplicate Customer Emails in a Marketing Campaign Imagine you are working on an email marketing campaign for your company. You have a list of customer emails, but some are duplicated. Using a set , you can remove duplicates efficiently before sending emails. Code Example: # List of customer emails (some duplicates) customer_emails = [ "alice@example.com" , "bob@example.com" , "charlie@example.com" , "alice@example.com" , "david@example.com" , "bob@example.com" ] # Convert list to a set to remove duplicates unique_emails = set (customer_emails) # Convert back to a list (if needed) unique_email_list = list (unique_emails) # Print the unique emails print ( "Unique customer emails:" , unique_email_list) Ou...
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How to Write ETL Logic in Python: Sample Code to Practice

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Here's an example Python code that uses the mysql-connector library to connect to a MySQL database, extract data from a table, transform it, and load it as a JSON file. Here's an example:







Python ETL Sample Code


import mysql.connector

import json


# Connect to the MySQL database

cnx = mysql.connector.connect(user='username', password='password',

                              host='localhost',

                              database='database_name')


# Define a cursor to execute SQL queries

cursor = cnx.cursor()


# Define the SQL query to extract data

query = ("SELECT column1, column2, column3 FROM table_name")


# Execute the SQL query

cursor.execute(query)


# Fetch all rows from the result set

rows = cursor.fetchall()


# Transform the rows into a list of dictionaries

result = []

for row in rows:

    result.append({'column1': row[0], 'column2': row[1], 'column3': row[2]})


# Save the result as a JSON file

with open('output.json', 'w') as outfile:

    json.dump(result, outfile)


# Close the cursor and database connection

cursor.close()

cnx.close()

In this example, you will need to replace username, password, localhost, database_name, table_name, column1, column2, and column3 with the appropriate values for your MySQL database and table. 


The code will extract the data from the specified table, transform it into a list of dictionaries, and save it as a JSON file named output.json.

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