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
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 Jamis,
I think there’s an issue with a test on chapter 6. I own the ebook, version P1.0 Feb. 2019.
This test doesn’t pass for me:
...
New
On the page xv there is an instruction to run bin/setup from the main folder. I downloaded the source code today (12/03/21) and can’t see...
New
A Common-Sense Guide to Data Structures and Algorithms, Second Edition by Jay Wengrow @jaywengrow
Hi,
I have the paperback version of t...
New
#book-python-testing-with-pytest-second-edition
Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...
New
I ran this command after installing the sample application:
$ cards add do something --owner Brian
And got a file not found error:
Fil...
New
Running mix deps.get in the sensor_hub directory fails with the following error:
** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
New
I think I might have found a problem involving SwitchCompat, thumbTint, and trackTint.
As entered, the SwitchCompat changes color to hol...
New
Is there any place where we can discuss the solutions to some of the exercises? I can figure most of them out, but am having trouble with...
New
Modern front-end development for Rails, second edition - Struggling to get the first chapter to work
After running /bin/setup, the first error was: The foreman' command exists in these Ruby versions: That was easy to fix: gem install fore...
New
Other popular topics
This looks like a stunning keycap set :orange_heart:
A LEGENDARY KEYBOARD LIVES ON
When you bought an Apple Macintosh computer in the e...
New
Do the test and post your score :nerd_face:
:keyboard:
If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
In case anyone else is wondering why Ruby 3 doesn’t show when you do asdf list-all ruby :man_facepalming: do this first:
asdf plugin-upd...
New
If you are experiencing Rails console using 100% CPU on your dev machine, then updating your development and test gems might fix the issu...
New
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
The File System Access API with Origin Private File System.
WebKit supports new API that makes it possible for web apps to create, open,...
New
I am trying to crate a game for the Nintendo switch, I wanted to use Java as I am comfortable with that programming language. Can you use...
New
Author Spotlight
Rebecca Skinner
@RebeccaSkinner
Welcome to our latest author spotlight, where we sit down with Rebecca Skinner, auth...
New
New
If you’re getting errors like this:
psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /ruby
- /wasm
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /centos
- /php
- /zig
- /deepseek
- /scala
- /textmate
- /lisp
- /sublime-text
- /react-native
- /nixos
- /debian
- /agda
- /kubuntu
- /arch-linux
- /deno
- /django
- /revery
- /ubuntu
- /nodejs
- /spring
- /manjaro
- /diversity
- /lua
- /julia
- /slackware
- /c







