This tag is for challenges related to hexadecimal, or base 16, a number system that often uses the digits 0 ‐ 9 and a ‐ f. Only use this tag on challenges specific to base 16, rather than generic [base-conversion] challenges

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Based off a Scratch project The pen extension in Scratch has a set pen color to () block. The () is normally a color dropdown, ...
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Take a list of 2-digit hexadecimal numbers as input, and output the binary value, replacing each 1 with an 'X', and each 0 with a space. For example Input = ...
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### Invert colors given a hex color code [duplicate]

So the challenge is, given a string containing a hex color code, write a function in any programming language that takes the string and inverts the color, e.g., ...
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### Reverse hex cipher

Characters in strings are sometimes represented as their ASCII hexadecimal codes. Printable characters have two hex digits in their representation. Swapping those digits leads to another character, ...
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### Write a regex that would increment a 2-digit hexadecimal number

Your regex will receive a string of the form !XX! #<extra> where X is any hexadecimal digit (0-9 and A-F capital letters ...
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### Scientific notation in Base-16

Input a scientific notation number (base 10), output scientific notation in base 16 (as defined below). Details In scientific notation, all non-zero numbers are written in the form $$m \times 10^n$$ ...
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### Code Golf Measurer © 2019

Code Golf Measurer © 2019 Hexdumps used with xxd look something like this: ...
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### Find the closest three-digit hex colour

In CSS, colours can be specified by a "hex triplet" - a three byte (six digit) hexadecimal number where each byte represents the red, green, or blue components of the colour. For instance, ...
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### Convert alphanumeric (base-36) sentences into hexadecimal (base-16) sentences

I use "sentence" here loosely to mean "any sequence of words separated by spaces" and "words" to mean "sequences of alphanumeric (hexatrigesimal) characters unseparated by spaces". Conversion is from ...
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### Python code to produce C++14 hex integer literal with ticks

tl;dr? See bottom for The Competition Integer literals While programming, the 64-bit hexadecimal literal 0x123456789abcdefL is difficult to gauge the size of. I ...
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### 0xDEADBEEF is not tasty, but still 0xFEEDBEEF

Inspired by "You had me at hello" Introduction For those who don't know, hexadecimal is a base system like decimal. Contrary to decimal however, it uses 16 (hence the name) digits instead of ...
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### Let's golf a BIBABOBU decoder

While I was traveling in the future, I noticed a funny game among kids circa 2275. When they don't want their great-great-great-great-grand parents to understand what they're saying, they use the ...
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### Render a monospaced bitmap font from image [closed]

Input is in this format: image fontwidth fontheight rowwidth xoffset yoffset xgap ygap non-existent charstart thetextitself thetextitself: The text that should ...
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### Swap the Endianness

As most of you probably know, (byte-addressable) hardware memories can be divided into two categories - little-endian and big-endian. In little-endian memories the bytes are numbered starting with 0 ...
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Convert a binary number (of any size) into a hexadecimal number. Input A POSITIVE binary number with just the 0s and 1s. A ...
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### How to convert HEX2 to RGBA?

The world of art is full of colour, but the world of the network is even fuller than the world of art of diferent colours and it's renderings. That's why we need to know how to convert one type of ...
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### Better Hex Color Codes for Your Internet

Hex triplets such as #ffffff (white) or #3764ef (blueish) are often used to denote RGB colors. They consist of ...
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### Rotate a camera; save an Astronaut

Note: Minor spoilers for The Martian are in this challenge. Read ahead with caution The Martian is a Science Fiction novel about astronaut and botanist extraordinaire, Mark Watney, who has been ...
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0xUsernames There's so many people using a messaging service that they're running out of space to store all the usernames! To fix this, they are going to start storing usernames as hexadecimal, where ...
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### Output the HTML colors

The 16-color CGA palette (also known as the HTML colors) is a set of 16 colors used by early graphics adapters. The goal of this challenge is to output all 16 of them, in hex format (...
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### Magic popcount numbers

There’s a famous tricky algorithm for counting the number of set bits in a 32-bit unsigned integer: ...
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### Reverse an xxd hexdump [duplicate]

Given an xxd hexdump such as this one: ...
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### The 3x3 Hexa Prime Square Puzzle

The 3x3 Hexa Prime Square Puzzle Introduction We consider 3x3 squares of hexadecimal digits (from 0 to F) such as: ...
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### The Woz Monitor

Challenge I've recently gotten into 8-bit computers and are fascinated with the workings of them and others alike; thus the objective of this code golf, is to replicate a portion of the Woz Monitor, ...
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### Convert to Bibi-binary

Bibi-binary is a numeric system invented by Boby Lapointe in order to represent numbers in letters which pronunciation seems funny. Your task is to convert decimal numbers into Bibi-binary! ...
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### Convert xxd output to shellcode

Taking some output from xxd and turning it into usable shellcode by hand is no fun, so your job is to automate the process. Rules Your submission can be a function, lambda, script, or any reasonable ...
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### "Add one" to every color in an image

You would simply take this image and make every color added one to every hexadecimal digit. For example, #49de5f would become ...
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### Print the input in hexadecimal [duplicate]

Challenges You need to do a program that outputs the input string to hexadecimal! For each character in the input string, convert it's ascii value to hexadecimal and output it out. Example ...
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### Convert a number to Hexadecimal

Challenge Here's a simple one. Write a function or program when given a number in base 10 as input, it will return or print that number's value in Hexadecimal. Examples ...
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In this challenge, you will receive an input, convert it to hexadecimal, make a couple changes, and output the result. Because they are only 16 characters in hexadecimal, your code will need to be as ...
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### Numbers that are actually letters

Given a non-negative integer input, write a program that converts the number to hexadecimal and returns a truthy value if the hexadecimal form of the number contains only the characters ...
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### Generate a hexdump of a file! [duplicate]

In this task, your goal is to write a program for generating hexdumps of files of arbitrary types. Input The input consists of a (relative or absolute) path to the file to be processed. It may be ...
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### Pronouncing Hex

Pronouncing Hex For those of you uninitiated with the show Silicon Valley, this challenge is inspired by an exchange that goes like this (YouTube): ...
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