joustava
Genetic Algorithms in Elixir: Code throws error (page 111)
Not sure if I’m doing something wrong here, but it seems that this piece of code will throw errors:
def fitness_function(chromosome) do
target = 'ILoveGeneticAlgorithms'
encrypted = 'LIjs`B`k`qlfDibjwlqmhv'
cipher = fn word, key -> Enum.map(word, & rem(&1 ^^^ key, 32768)) end
key =
chromosome.genes
|> Enum.map(&Integer.to_string/1)
|> Enum.join("")
|> String.to_integer(2)
guess = List.to_string(cipher.(encrypted, key))
String.jaro_distance(target, guess)
end
As
String.jaro_distance(target, guess)
Doesn’t expect ‘charlists’ but binaries
** (FunctionClauseError) no function clause matching in String.Unicode.graphemes/1
The following arguments were given to String.Unicode.graphemes/1:
# 1
'ILoveGeneticAlgorithms'
Attempted function clauses (showing 1 out of 1):
def graphemes(binary) when is_binary(binary)
(elixir 1.10.3) lib/elixir/unicode/unicode.ex:252: String.Unicode.graphemes/1
(elixir 1.10.3) lib/string.ex:2488: String.jaro_distance/2
(genetic 0.1.0) lib/genetic.ex:24: anonymous fn/2 in Genetic.evaluate/3
(elixir 1.10.3) lib/enum.ex:1396: Enum."-map/2-lists^map/1-0-"/2
(genetic 0.1.0) lib/genetic.ex:23: Genetic.evaluate/3
(genetic 0.1.0) lib/genetic.ex:116: Genetic.evolve/6
scripts/code_breaker.exs:39: (file)
I’m running this on:
⟩ elixir --version
Erlang/OTP 23 [erts-11.0.2] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]
Elixir 1.10.3 (compiled with Erlang/OTP 23)
Not sure if something has changed recently regarding this issue.
Also, it seems the capture operator ‘&’ is in the wrong place in the book and should be moved before the call to ‘rem’ otherwise a
** (ArithmeticError) bad argument in arithmetic expression: rem(#Function<1.106933999/1 in CodeBreaker.fitness_function/1>, 32768)
:erlang.rem(#Function<1.106933999/1 in CodeBreaker.fitness_function/1>, 32768)
scripts/code_breaker.exs:16: anonymous fn/2 in CodeBreaker.fitness_function/1
(genetic 0.1.0) lib/genetic.ex:24: anonymous fn/2 in Genetic.evaluate/3
(elixir 1.10.3) lib/enum.ex:1396: Enum."-map/2-lists^map/1-0-"/2
(genetic 0.1.0) lib/genetic.ex:23: Genetic.evaluate/3
(genetic 0.1.0) lib/genetic.ex:116: Genetic.evolve/6
scripts/code_breaker.exs:33: (file)
will occur.
I think on the next page in the iex example it is the correct way.
First Post!
adkelley
Strings in Elixir are inserted between double quotes. Therefore change: target = 'ILoveGeneticAlgorithms' to: target = "ILoveGeneticAlgorithms"
Popular Pragmatic Bookshelf topics
page 37
ANTLRInputStream input = new ANTLRInputStream(is);
as of ANTLR 4 .8 should be:
CharStream stream = CharStreams.fromStream(i...
New
Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...
New
Hi @Margaret ,
On page VII the book tells us the example and snippets will be all using Elixir version 1.11
But on page 3 almost the en...
New
Hi! I know not the intentions behind this narrative when called, on page XI:
mount() |> handle_event() |> render()
but the correc...
New
“The ProductLive.Index template calls a helper function, live_component/3, that in turn calls on the modal component. ”
Excerpt From: Br...
New
When I run the coverage example to report on missing lines, I get:
pytest --cov=cards --report=term-missing ch7
ERROR: usage: pytest [op...
New
Hi,
I completed chapter 6 but am getting the following error when running:
thread 'main' panicked at 'Failed to load texture: IoError(O...
New
Hey there,
I’m enjoying this book and have learned a few things alredayd. However, in Chapter 4 I believe we are meant to see the “>...
New
The markup used to display the uploaded image results in a Phoenix.LiveView.HTMLTokenizer.ParseError error.
lib/pento_web/live/product_l...
New
Hello @herbert ! Trying to get the very first “Hello, Bracket Terminal!" example to run (p. 53). I develop on an Amazon EC2 instance runn...
New
Other popular topics
Learn from the award-winning programming series that inspired the Elixir language, and go on a step-by-step journey through the most impo...
New
Which, if any, games do you play? On what platform?
I just bought (and completed) Minecraft Dungeons for my Nintendo Switch. Other than ...
New
We have a thread about the keyboards we have, but what about nice keyboards we come across that we want? If you have seen any that look n...
New
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
New
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
New
Hello everyone! This thread is to tell you about what authors from The Pragmatic Bookshelf are writing on Medium.
New
Use WebRTC to build web applications that stream media and data in real time directly from one user to another, all in the browser.
...
New
Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...
New
A Brief Review of the Minisforum V3 AMD Tablet.
Update: I have created an awesome-minisforum-v3 GitHub repository to list information fo...
New
Node.js v22.14.0 has been released.
Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /java
- /emacs
- /haskell
- /svelte
- /typescript
- /onivim
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /deepseek
- /zig
- /centos
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /deno
- /kubuntu
- /arch-linux
- /nodejs
- /spring
- /ubuntu
- /revery
- /manjaro
- /diversity
- /lua
- /julia
- /markdown
- /c









