Haskell

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About Haskell

Practice

150 contributors

321 mentors

24,661
students have developed their Haskell skills on Exercism.

Students

24,661

Submissions

395,759

Mentoring Discussions

14,268

The Haskell track needs attention ⚠️

Building

Build

Use your knowledge to build the Haskell track itself

150 contributors

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. Haskell is currently utilising a Version 1 Test Runner. Find out more.

Usage statistics

Total Test Runner Runs

328,686

Test Run Pass Rate

31.2% (102657)

Test Run Fail Rate

65.5% (215194)

Test Run Error Rate

3.3% (10835)

Build Analyzers

Learn More

Build an Analyzer for Haskell: 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 128 practice exercises. Find out more.

Usage statistics

96 active practice exercises

Started

Attempts

Completions

Mentoring requests

Hello World

16,381

23,753 (avg. 1.5)

14,121 (86.2%)

6 (0.0%)

Leap

12,986

39,083 (avg. 3.0)

10,107 (77.8%)

2,707 (20.8%)

Space Age

8,369

27,311 (avg. 3.3)

6,524 (78.0%)

1,362 (16.3%)

Pangram

6,016

27,660 (avg. 4.6)

4,416 (73.4%)

888 (14.8%)

Bob

5,644

37,875 (avg. 6.7)

4,198 (74.4%)

1,186 (21.0%)

Collatz Conjecture

3,879

19,781 (avg. 5.1)

3,097 (79.8%)

562 (14.5%)

RNA Transcription

4,580

15,753 (avg. 3.4)

3,827 (83.6%)

1,150 (25.1%)

Nucleotide Count

3,138

10,586 (avg. 3.4)

2,250 (71.7%)

592 (18.9%)

Sum of Multiples

3,104

10,448 (avg. 3.4)

2,536 (81.7%)

419 (13.5%)

Grains

2,960

9,793 (avg. 3.3)

2,649 (89.5%)

520 (17.6%)

Acronym

3,292

10,965 (avg. 3.3)

1,769 (53.7%)

168 (5.1%)

Strain

2,572

4,473 (avg. 1.7)

2,251 (87.5%)

198 (7.7%)

Anagram

2,548

8,060 (avg. 3.2)

2,026 (79.5%)

354 (13.9%)

Clock

1,637

5,206 (avg. 3.2)

1,218 (74.4%)

71 (4.3%)

Crypto Square

1,227

4,675 (avg. 3.8)

829 (67.6%)

75 (6.1%)

Luhn

1,241

4,292 (avg. 3.5)

932 (75.1%)

72 (5.8%)

Nth Prime

1,343

4,471 (avg. 3.3)

928 (69.1%)

36 (2.7%)

Minesweeper

885

2,608 (avg. 2.9)

508 (57.4%)

46 (5.2%)

Perfect Numbers

1,948

4,389 (avg. 2.3)

1,467 (75.3%)

70 (3.6%)

Phone Number

1,573

3,993 (avg. 2.5)

1,292 (82.1%)

177 (11.3%)

Secret Handshake

943

2,161 (avg. 2.3)

748 (79.3%)

22 (2.3%)

Pascal's Triangle

849

1,933 (avg. 2.3)

668 (78.7%)

31 (3.7%)

Binary Search Tree

1,046

3,376 (avg. 3.2)

737 (70.5%)

73 (7.0%)

Queen Attack

748

2,361 (avg. 3.2)

557 (74.5%)

50 (6.7%)

Word Count

1,096

2,944 (avg. 2.7)

880 (80.3%)

316 (28.8%)

Wordy

494

1,483 (avg. 3.0)

287 (58.1%)

31 (6.3%)

Hamming

2,357

5,161 (avg. 2.2)

2,032 (86.2%)

448 (19.0%)

Robot Simulator

1,028

2,964 (avg. 2.9)

832 (80.9%)

74 (7.2%)

Twelve Days

694

1,503 (avg. 2.2)

514 (74.1%)

12 (1.7%)

Saddle Points

549

1,134 (avg. 2.1)

340 (61.9%)

9 (1.6%)

Food Chain

359

597 (avg. 1.7)

230 (64.1%)

8 (2.2%)

OCR Numbers

408

816 (avg. 2.0)

286 (70.1%)

16 (3.9%)

Change

449

1,369 (avg. 3.0)

190 (42.3%)

16 (3.6%)

Go Counting

283

411 (avg. 1.5)

102 (36.0%)

5 (1.8%)

Resistor Color Duo

649

911 (avg. 1.4)

538 (82.9%)

12 (1.8%)

D&D Character

470

1,126 (avg. 2.4)

269 (57.2%)

10 (2.1%)

Resistor Color Trio

480

1,173 (avg. 2.4)

344 (71.7%)

9 (1.9%)

Run-Length Encoding

1,106

2,272 (avg. 2.1)

880 (79.6%)

43 (3.9%)

House

401

534 (avg. 1.3)

286 (71.3%)

15 (3.7%)

Proverb

391

816 (avg. 2.1)

256 (65.5%)

2 (0.5%)

Simple Linked List

1,068

2,185 (avg. 2.0)

841 (78.7%)

86 (8.1%)

Custom Set

416

1,357 (avg. 3.3)

247 (59.4%)

14 (3.4%)

Bowling

263

708 (avg. 2.7)

108 (41.1%)

4 (1.5%)

ISBN Verifier

781

1,719 (avg. 2.2)

604 (77.3%)

20 (2.6%)

Protein Translation

582

1,647 (avg. 2.8)

427 (73.4%)

16 (2.7%)

Yacht

628

3,094 (avg. 4.9)

390 (62.1%)

6 (1.0%)

Pythagorean Triplet

551

1,239 (avg. 2.2)

381 (69.1%)

14 (2.5%)

Rotational Cipher

346

523 (avg. 1.5)

263 (76.0%)

11 (3.2%)

Spiral Matrix

269

376 (avg. 1.4)

165 (61.3%)

2 (0.7%)

Alphametics

227

197 (avg. 0.9)

82 (36.1%)

1 (0.4%)

Beer Song

825

1,609 (avg. 2.0)

702 (85.1%)

130 (15.8%)

List Ops

830

1,867 (avg. 2.2)

660 (79.5%)

97 (11.7%)

Matrix

459

784 (avg. 1.7)

326 (71.0%)

31 (6.8%)

Binary Search

428

727 (avg. 1.7)

226 (52.8%)

3 (0.7%)

Parallel Letter Frequency

311

434 (avg. 1.4)

157 (50.5%)

18 (5.8%)

Transpose

264

525 (avg. 2.0)

140 (53.0%)

2 (0.8%)

Poker

234

238 (avg. 1.0)

76 (32.5%)

2 (0.9%)

Lens Person

315

572 (avg. 1.8)

149 (47.3%)

14 (4.4%)

Triangle

862

1,378 (avg. 1.6)

729 (84.6%)

49 (5.7%)

Meetup

527

801 (avg. 1.5)

400 (75.9%)

65 (12.3%)

Sieve

395

796 (avg. 2.0)

291 (73.7%)

10 (2.5%)

Palindrome Products

261

516 (avg. 2.0)

154 (59.0%)

8 (3.1%)

Simple Cipher

303

612 (avg. 2.0)

177 (58.4%)

13 (4.3%)

Connect

188

168 (avg. 0.9)

85 (45.2%)

3 (1.6%)

POV

219

378 (avg. 1.7)

90 (41.1%)

6 (2.7%)

Difference of Squares

1,724

4,228 (avg. 2.5)

1,469 (85.2%)

95 (5.5%)

Raindrops

927

1,601 (avg. 1.7)

788 (85.0%)

79 (8.5%)

Kindergarten Garden

633

972 (avg. 1.5)

466 (73.6%)

23 (3.6%)

All Your Base

506

1,049 (avg. 2.1)

338 (66.8%)

12 (2.4%)

Allergies

515

741 (avg. 1.4)

420 (81.6%)

54 (10.5%)

Series

477

1,107 (avg. 2.3)

327 (68.6%)

15 (3.1%)

Bank Account

364

616 (avg. 1.7)

242 (66.5%)

52 (14.3%)

Rail Fence Cipher

206

223 (avg. 1.1)

119 (57.8%)

4 (1.9%)

Sublist

988

1,675 (avg. 1.7)

897 (90.8%)

220 (22.3%)

SGF Parsing

184

339 (avg. 1.8)

90 (48.9%)

5 (2.7%)

Zipper

254

421 (avg. 1.7)

140 (55.1%)

6 (2.4%)

Armstrong Numbers

1,064

3,369 (avg. 3.2)

758 (71.2%)

20 (1.9%)

ETL

1,017

1,408 (avg. 1.4)

862 (84.8%)

91 (8.9%)

Scrabble Score

729

1,258 (avg. 1.7)

630 (86.4%)

81 (11.1%)

Roman Numerals

566

845 (avg. 1.5)

446 (78.8%)

69 (12.2%)

Atbash Cipher

402

662 (avg. 1.6)

322 (80.1%)

59 (14.7%)

Pig Latin

200

234 (avg. 1.2)

132 (66.0%)

6 (3.0%)

Robot Name

449

750 (avg. 1.7)

307 (68.4%)

107 (23.8%)

Say

206

284 (avg. 1.4)

123 (59.7%)

5 (2.4%)

Dominoes

247

449 (avg. 1.8)

95 (38.5%)

4 (1.6%)

Accumulate

1,904

2,704 (avg. 1.4)

1,784 (93.7%)

340 (17.9%)

Complex Numbers

543

1,462 (avg. 2.7)

384 (70.7%)

4 (0.7%)

Largest Series Product

567

1,150 (avg. 2.0)

417 (73.5%)

30 (5.3%)

Prime Factors

587

844 (avg. 1.4)

458 (78.0%)

41 (7.0%)

Matching Brackets

486

968 (avg. 2.0)

308 (63.4%)

15 (3.1%)

Linked List

384

679 (avg. 1.8)

169 (44.0%)

18 (4.7%)

Zebra Puzzle

205

162 (avg. 0.8)

95 (46.3%)

3 (1.5%)

Forth

294

617 (avg. 2.1)

101 (34.4%)

5 (1.7%)

Diamond

792

1,146 (avg. 1.4)

530 (66.9%)

20 (2.5%)

Grade School

1,501

2,383 (avg. 1.6)

1,095 (73.0%)

156 (10.4%)

Isogram

1,119

1,996 (avg. 1.8)

865 (77.3%)

36 (3.2%)

5 deprecated practice exercises

Started

Attempts

Completions

Mentoring requests

Binary

141

274 (avg. 1.9)

137 (97.2%)

65 (46.1%)

Gigasecond

536

812 (avg. 1.5)

532 (99.3%)

116 (21.6%)

Hexadecimal

152 (avg. 1.8)

83 (96.5%)

33 (38.4%)

Octal

92 (avg. 1.6)

54 (94.7%)

19 (33.3%)

Trinary

82 (avg. 1.5)

51 (94.4%)

15 (27.8%)

32 unimplemented practice exercises

Affine Cipher

Book Store

Bottle Song

Circular Buffer

DOT DSL

Darts

Error Handling

Flatten Array

Grep

Hangman

High Scores

Killer Sudoku Helper

Knapsack

Ledger

Markdown

Micro Blog

PaaS I/O

REST API

Rational Numbers

React

Rectangles

Reverse String

Satellite

Scale Generator

Square Root

State of Tic-Tac-Toe

Tournament

Tree Building

Two Bucket

Two-Fer

Variable Length Quantity

View data

Word Search

View data

1 foregone practice exercise

Resistor Color

View data

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24,661 students have developed their Haskell skills on Exercism.

The Haskell track needs attention ⚠️

Build

Build Test Runners

Usage statistics

Build Analyzers

Build Representers

Create Practice Exercises

Usage statistics

We 💙 our volunteers

24,661
students have developed their Haskell skills on Exercism.