237
students have developed their Red skills on Exercism.

Students
237
Submissions
5,046
Mentoring Discussions
10

The Red track needs attention ⚠️

Building

Build

Use your knowledge to build the Red track itself

Build Test Runners

Learn More

Create Test Runners that have the single responsibility of taking a solution, running all tests and returning a standardized output.

Usage statistics

Total Test Runner Runs
5,030
Test Run Pass Rate
20.2% (1014)
Test Run Fail Rate
69.6% (3499)
Test Run Error Rate
10.3% (517)

Build Analyzers

Learn More

Build an Analyzer for Red: Exercism's analyzers automatically assess student's submissions and provide mentor-style commentary.

Next goal: Build an Analyzer. Find out more.

Build Representers

Learn More

Build a Representer: a bit of code that has the single responsibility of taking a solution and returning a normalized representation of it.

Next goal: Build a Representer. Find out more.

Create Practice Exercises

Learn More

Practice Exercises are exercises designed to allow students to solve an arbitrary problem, with the aim of them making use of the concepts they have learned so far.

Next goal: Implement at least 30 practice exercises. Find out more.

Usage statistics

20 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
207
322 (avg. 1.6)
166 (80.2%)
0 (0.0%)
Two Fer Two Fer
120
686 (avg. 5.7)
74 (61.7%)
4 (3.3%)
Reverse String Reverse String
83
800 (avg. 9.6)
61 (73.5%)
2 (2.4%)
Resistor Color Resistor Color
60
311 (avg. 5.2)
51 (85.0%)
1 (1.7%)
Protein Translation Protein Translation
47
468 (avg. 10.0)
34 (72.3%)
1 (2.1%)
Space Age Space Age
46
276 (avg. 6.0)
40 (87.0%)
0 (0.0%)
Raindrops Raindrops
43
233 (avg. 5.4)
36 (83.7%)
2 (4.7%)
Resistor Color Duo Resistor Color Duo
24
148 (avg. 6.2)
22 (91.7%)
0 (0.0%)
Darts Darts
27
117 (avg. 4.3)
23 (85.2%)
0 (0.0%)
Rotational Cipher Rotational Cipher
22
261 (avg. 11.9)
14 (63.6%)
1 (4.5%)
Roman Numerals Roman Numerals
24
257 (avg. 10.7)
19 (79.2%)
0 (0.0%)
Resistor Color Trio Resistor Color Trio
17
338 (avg. 19.9)
15 (88.2%)
1 (5.9%)
Largest Series Product Largest Series Product
13
375 (avg. 28.8)
12 (92.3%)
1 (7.7%)
SGF Parsing SGF Parsing
11
99 (avg. 9.0)
3 (27.3%)
1 (9.1%)
High Scores High Scores
10
32 (avg. 3.2)
7 (70.0%)
0 (0.0%)
Run-Length Encoding Run-Length Encoding
10
50 (avg. 5.0)
7 (70.0%)
0 (0.0%)
Simple Linked List Simple Linked List
10
11 (avg. 1.1)
6 (60.0%)
0 (0.0%)
Bowling Bowling
9
113 (avg. 12.6)
4 (44.4%)
1 (11.1%)
POV POV
7
88 (avg. 12.6)
3 (42.9%)
0 (0.0%)
Circular Buffer Circular Buffer
10
61 (avg. 6.1)
6 (60.0%)
0 (0.0%)
108 unimplemented practice exercises
Acronym Acronym
Affine Cipher Affine Cipher
All Your Base All Your Base
Allergies Allergies
Alphametics Alphametics
Anagram Anagram
Armstrong Numbers Armstrong Numbers
Atbash Cipher Atbash Cipher
Bank Account Bank Account
Binary Search Binary Search
Binary Search Tree Binary Search Tree
Bob Bob
Book Store Book Store
Bottle Song Bottle Song
Change Change
Clock Clock
Collatz Conjecture Collatz Conjecture
Complex Numbers Complex Numbers
Connect Connect
Crypto Square Crypto Square
Custom Set Custom Set
D&D Character D&D Character
DOT DSL DOT DSL
Diamond Diamond
Difference of Squares Difference of Squares
Dominoes Dominoes
ETL ETL
Error Handling Error Handling
Flatten Array Flatten Array
Food Chain Food Chain
Forth Forth
Gigasecond Gigasecond
Go Counting Go Counting
Grade School Grade School
Grains Grains
Grep Grep
Hamming Hamming
Hangman Hangman
House House
ISBN Verifier ISBN Verifier
Isogram Isogram
Killer Sudoku Helper Killer Sudoku Helper
Kindergarten Garden Kindergarten Garden
Knapsack Knapsack
Leap Leap
Ledger Ledger
Lens Person Lens Person
Linked List Linked List
List Ops List Ops
Luhn Luhn
Markdown Markdown
Matching Brackets Matching Brackets
Matrix Matrix
Meetup Meetup
Micro Blog Micro Blog
Minesweeper Minesweeper
Nth Prime Nth Prime
Nucleotide Count Nucleotide Count
OCR Numbers OCR Numbers
PaaS I/O PaaS I/O
Palindrome Products Palindrome Products
Pangram Pangram
Parallel Letter Frequency Parallel Letter Frequency
Pascal's Triangle Pascal's Triangle
Perfect Numbers Perfect Numbers
Phone Number Phone Number
Pig Latin Pig Latin
Poker Poker
Prime Factors Prime Factors
Proverb Proverb
Pythagorean Triplet Pythagorean Triplet
Queen Attack Queen Attack
REST API REST API
RNA Transcription RNA Transcription
Rail Fence Cipher Rail Fence Cipher
Rational Numbers Rational Numbers
React React
Rectangles Rectangles
Robot Name Robot Name
Robot Simulator Robot Simulator
Saddle Points Saddle Points
Satellite Satellite
Say Say
Scale Generator Scale Generator
Scrabble Score Scrabble Score
Secret Handshake Secret Handshake
Series Series
Sieve Sieve
Simple Cipher Simple Cipher
Spiral Matrix Spiral Matrix
Square Root Square Root
State of Tic-Tac-Toe State of Tic-Tac-Toe
Strain Strain
Sublist Sublist
Sum of Multiples Sum of Multiples
Tournament Tournament
Transpose Transpose
Tree Building Tree Building
Triangle Triangle
Twelve Days Twelve Days
Two Bucket Two Bucket
Variable Length Quantity Variable Length Quantity
Word Count Word Count
Word Search Word Search
Wordy Wordy
Yacht Yacht
Zebra Puzzle Zebra Puzzle
Zipper Zipper