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Python & Data Engineer Interview Cheat Sheet

This cheat sheet contains runnable Python examples across Core Python, ETL/Data Processing, Algorithmic Thinking, Pandas/SQL, and Real-world Scenarios.

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1️⃣ Core Python

Word frequency in string

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🕵️‍♂️ Synthetic Monitoring with Selenium + CDP (Analytics-Safe)

This script is a lightweight synthetic monitoring tool using Selenium + Chrome DevTools Protocol (CDP) that allows you to load a web page without triggering internal or external analytics scripts.

Ideal for enterprise use cases where you want to:

• Monitor uptime or check page content
• Avoid polluting internal analytics data
• Block self-hosted tracking domains

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import boto3
import hashlib
from dotenv import load_dotenv
from botocore.exceptions import ClientError

load_dotenv()

# Initialize DynamoDB client
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('gen_cache')

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import csv

def position_to_row_col(csv_file_path, byte_position):
    try:
        with open(csv_file_path, 'r', encoding='utf-8') as file:
            csv_reader = csv.reader(file)
            current_pos = 0
            
            for row_num, row in enumerate(csv_reader, start=1):
                for col_num, cell in enumerate(row, start=1):

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import csv
import re

def has_special_characters(text):
    # Define a regular expression to match non-alphanumeric and non-Markdown special characters
    special_char_pattern = re.compile(r'[^a-zA-Z0-9\s,.!?;:()"\'*?_~`\-+=<>{}\[\]\\\\|/^#]', re.UNICODE)
    
    return bool(special_char_pattern.search(text))

def find_rows_with_special_characters(file_path):

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MySQL Cheat Sheet

Help with SQL commands to interact with a MySQL database

MySQL Locations

• Mac /usr/local/mysql/bin
• Windows /Program Files/MySQL/MySQL version/bin
• Xampp /xampp/mysql/bin

Add mysql to your PATH