Guides · page 11 of 14
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ROT13 in Programming: Implementing and Using ROT13 in Code
ROT13 is simple to implement but appears in real codebases for obfuscation, puzzle games, and filter evasion. Here's how to implement ROT13 in JavaScript, Python, and Go, and...
ROT13 in Games, Forums, and Usenet: A Cultural History
ROT13 has been used since the 1980s to hide spoilers on Usenet, obscure puzzle answers, and encode jokes in forum posts. Learn the cultural history of ROT13, its revival in...
Sentence Length and Readability: How Long Should a Sentence Be?
Sentence counters do more than count. Learn how average sentence length, sentence variety, and reading level scores affect comprehension and whether Google ranks your content.
SHA-256 Hash: How It Works and How to Use It in Code
SHA-256 produces a 256-bit (64 hex character) hash. It's used for data integrity verification, digital signatures, and file checksums. Here's how SHA-256 works and how to...
Snake Case: What It Is, When to Use It, and How to Convert
Snake case uses underscores between words in lowercase: hello_world, user_first_name. It's the standard naming convention for Python, SQL, and file names. Here's when to use...
SQL CTEs (Common Table Expressions): WITH Clause Guide
Common Table Expressions (CTEs) use the WITH clause to create named temporary result sets. Learn how to write readable CTEs, use recursive CTEs for hierarchical data, and when...
SQL Joins Explained: INNER, LEFT, RIGHT, and FULL JOIN
SQL joins combine rows from multiple tables. INNER JOIN returns matching rows, LEFT JOIN returns all from the left table, RIGHT JOIN from the right, FULL JOIN returns all rows....
SQL Query Optimization: Write Faster Queries with Indexes and Explain
Slow SQL queries are usually missing indexes, using table scans, or written inefficiently. Here's how to use EXPLAIN to find bottlenecks, add the right indexes, and write...
SQL Subqueries: Correlated, Scalar, and IN vs EXISTS
SQL subqueries nest one query inside another. Learn the difference between correlated and non-correlated subqueries, scalar subqueries, and when to use IN vs EXISTS vs JOIN for...
SQL Window Functions: ROW_NUMBER, RANK, LAG, and More
SQL window functions calculate values across a set of rows related to the current row without collapsing them into groups. Here's how ROW_NUMBER, RANK, LAG, LEAD, and SUM OVER...
Subnet Mask Explained: How Subnetting and Network Masks Work
A subnet mask separates the network portion from the host portion of an IP address. Here's how subnet masks work, how to read CIDR notation, and how to calculate usable hosts...
Subnetting Guide: How to Calculate Subnet Masks and IP Ranges
Subnetting divides a network into smaller subnetworks. Here's how CIDR notation, subnet masks, and IP address ranges work, with calculation examples and a cheat sheet.
SVG Favicon: Modern Vector Favicons for Any Screen
SVG favicons scale perfectly at any size and support dark mode via CSS media queries. Here's how to create an SVG favicon, implement it correctly, and use dark mode variants.
String Case Conversion in JavaScript: toUpperCase, toLowerCase, and More
JavaScript has built-in methods for uppercase and lowercase conversion, but converting between camelCase, snake_case, and kebab-case requires custom code. Here's a complete...
Text Diff Algorithms: How Myers, LCS, and Patience Diff Work
Text diff tools use algorithms like Myers diff, LCS (Longest Common Subsequence), and Patience diff to find minimal edit distances between texts. Understand how these work and...
Timestamp to Date: Convert Unix Timestamps to Human-Readable Dates
Converting a Unix timestamp to a date requires knowing whether it's seconds or milliseconds and what timezone to display in. Here's how to convert timestamps in code and why...
Two's Complement: How Computers Represent Negative Numbers
Two's complement is the standard way CPUs store negative integers. Understanding it explains sign overflow, bit masking, and why -1 in binary is all ones. Here's the math and...
ULID Generator: Universally Unique Lexicographically Sortable Identifiers
ULID is a 26-character sortable unique identifier that embeds a millisecond timestamp prefix. Unlike UUID v4, ULIDs sort chronologically. Here's how ULIDs work and when to use...
Unix Timestamp: What Epoch Time Is and How to Convert It
A Unix timestamp is seconds since January 1, 1970 UTC. It's the standard time representation for APIs, databases, and logs. Here's how to convert timestamps and avoid timezone...
Uppercase Text Converter: Convert Text to ALL CAPS or Title Case
Converting text to uppercase, lowercase, or title case is a common need for headings, constants, and formatting. Here's how to use an uppercase converter online and convert...
URL Encode Decode: Encode and Decode URLs Online
URL encoding converts special characters to percent-encoded sequences (%20 for space, %2F for slash). Here's when to encode, what gets encoded, and the difference between...
URL Encoding in Python: urllib.parse, requests, and FastAPI
Python's urllib.parse module provides quote, quote_plus, and urlencode for URL encoding. Here's how to encode URLs and query strings correctly in Python, requests library, and...
URL Encoding in JavaScript: encodeURIComponent vs encodeURI
JavaScript has two URL encoding functions: encodeURI for full URLs and encodeURIComponent for individual components. Learn the difference, when to use each, how to encode query...
URL Encoding Special Characters: Which Characters to Encode and When
URL encoding converts special characters to percent-encoded sequences (%20, %26, etc.). Here's which characters require encoding in query strings vs path segments, and how to...