223
students have developed their LFE skills on Exercism.

Students
223
Submissions
709
Mentoring Discussions
23

The LFE track needs attention ⚠️

Building

Build

Use your knowledge to build the LFE 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.

Next goal: Get Test Runners to Version 2. LFE is currently utilising a Version 1 Test Runner. Find out more.

Usage statistics

Total Test Runner Runs
600
Test Run Pass Rate
32.3% (194)
Test Run Fail Rate
61.3% (368)
Test Run Error Rate
6.3% (38)

Build Analyzers

Learn More

Build an Analyzer for LFE: 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 40 practice exercises. Find out more.

Usage statistics

31 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
99
102 (avg. 1.0)
72 (72.7%)
0 (0.0%)
Allergies Allergies
21
97 (avg. 4.6)
1 (4.8%)
0 (0.0%)
Anagram Anagram
16
26 (avg. 1.6)
7 (43.8%)
0 (0.0%)
Atbash Cipher Atbash Cipher
7
27 (avg. 3.9)
3 (42.9%)
0 (0.0%)
Bank Account Bank Account
3
53 (avg. 17.7)
0 (0.0%)
1 (33.3%)
Beer Song Beer Song
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Binary Binary
5
32 (avg. 6.4)
3 (60.0%)
0 (0.0%)
Bob Bob
18
92 (avg. 5.1)
14 (77.8%)
3 (16.7%)
Circular Buffer Circular Buffer
4
57 (avg. 14.3)
1 (25.0%)
1 (25.0%)
Clock Clock
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Difference of Squares Difference of Squares
4
5 (avg. 1.3)
1 (25.0%)
0 (0.0%)
ETL ETL
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Gigasecond Gigasecond
3
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Grade School Grade School
4
3 (avg. 0.8)
2 (50.0%)
0 (0.0%)
Grains Grains
7
8 (avg. 1.1)
6 (85.7%)
0 (0.0%)
Hamming Hamming
12
33 (avg. 2.8)
10 (83.3%)
1 (8.3%)
Largest Series Product Largest Series Product
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Leap Leap
51
66 (avg. 1.3)
40 (78.4%)
9 (17.6%)
Luhn Luhn
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Meetup Meetup
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Nucleotide Count Nucleotide Count
7
6 (avg. 0.9)
5 (71.4%)
0 (0.0%)
Parallel Letter Frequency Parallel Letter Frequency
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Phone Number Phone Number
5
2 (avg. 0.4)
2 (40.0%)
0 (0.0%)
RNA Transcription RNA Transcription
26
40 (avg. 1.5)
23 (88.5%)
6 (23.1%)
Robot Simulator Robot Simulator
4
2 (avg. 0.5)
2 (50.0%)
0 (0.0%)
Series Series
2
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Space Age Space Age
8
9 (avg. 1.1)
7 (87.5%)
0 (0.0%)
Strain Strain
10
14 (avg. 1.4)
9 (90.0%)
0 (0.0%)
Sum of Multiples Sum of Multiples
13
22 (avg. 1.7)
10 (76.9%)
2 (15.4%)
Trinary Trinary
3
0 (avg. 0.0)
0 (0.0%)
0 (0.0%)
Word Count Word Count
5
3 (avg. 0.6)
3 (60.0%)
0 (0.0%)
1 deprecated practice exercises
Started
Attempts
Completions
Mentoring requests
Accumulate Accumulate
3
10 (avg. 3.3)
3 (100.0%)
2 (66.7%)
100 unimplemented practice exercises
Acronym Acronym
Affine Cipher Affine Cipher
All Your Base All Your Base
Alphametics Alphametics
Armstrong Numbers Armstrong Numbers
Binary Search Binary Search
Binary Search Tree Binary Search Tree
Book Store Book Store
Bottle Song Bottle Song
Bowling Bowling
Change Change
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
Darts Darts
Diamond Diamond
Dominoes Dominoes
Error Handling Error Handling
Flatten Array Flatten Array
Food Chain Food Chain
Forth Forth
Go Counting Go Counting
Grep Grep
Hangman Hangman
High Scores High Scores
House House
ISBN Verifier ISBN Verifier
Isogram Isogram
Killer Sudoku Helper Killer Sudoku Helper
Kindergarten Garden Kindergarten Garden
Knapsack Knapsack
Ledger Ledger
Lens Person Lens Person
Linked List Linked List
List Ops List Ops
Markdown Markdown
Matching Brackets Matching Brackets
Matrix Matrix
Micro Blog Micro Blog
Minesweeper Minesweeper
Nth Prime Nth Prime
OCR Numbers OCR Numbers
POV POV
PaaS I/O PaaS I/O
Palindrome Products Palindrome Products
Pangram Pangram
Pascal's Triangle Pascal's Triangle
Perfect Numbers Perfect Numbers
Pig Latin Pig Latin
Poker Poker
Prime Factors Prime Factors
Protein Translation Protein Translation
Proverb Proverb
Pythagorean Triplet Pythagorean Triplet
Queen Attack Queen Attack
REST API REST API
Rail Fence Cipher Rail Fence Cipher
Raindrops Raindrops
Rational Numbers Rational Numbers
React React
Rectangles Rectangles
Resistor Color Resistor Color
Resistor Color Duo Resistor Color Duo
Resistor Color Trio Resistor Color Trio
Reverse String Reverse String
Robot Name Robot Name
Roman Numerals Roman Numerals
Rotational Cipher Rotational Cipher
Run-Length Encoding Run-Length Encoding
SGF Parsing SGF Parsing
Saddle Points Saddle Points
Satellite Satellite
Say Say
Scale Generator Scale Generator
Scrabble Score Scrabble Score
Secret Handshake Secret Handshake
Sieve Sieve
Simple Cipher Simple Cipher
Simple Linked List Simple Linked List
Spiral Matrix Spiral Matrix
Square Root Square Root
State of Tic-Tac-Toe State of Tic-Tac-Toe
Sublist Sublist
Tournament Tournament
Transpose Transpose
Tree Building Tree Building
Triangle Triangle
Twelve Days Twelve Days
Two Bucket Two Bucket
Two-Fer Two-Fer
Variable Length Quantity Variable Length Quantity
Word Search Word Search
Wordy Wordy
Yacht Yacht
Zebra Puzzle Zebra Puzzle
Zipper Zipper