Effective Haskell - inaccurate description of filter example (page 61)
On p.61 in Chapter 2, the following is described as finding “the sum of the first ten odd numbers”:
λ (foldr (+) 0 . filter odd) [0..10]
25
In fact, this code sums the odd numbers between 0 and 10 – that is, the first five odd numbers. For the sum of the first ten odd numbers, you’d probably want something like
λ (foldr (+) 0 . map (\x -> 2 * x + 1)) [0..9]
100
Popular Pragprog topics
Title: Web Development with Clojure, Third Edition, pg 116
Hi - I just started chapter 5 and I am stuck on page 116 while trying to star...
New
your book suggests to use Image.toByteData() to convert image to bytes, however I get the following error: "the getter ‘toByteData’ ...
New
Hi,
build fails on:
bracket-lib = “~0.8.1”
when running on Mac Mini M1 Rust version 1.5.0:
Compiling winit v0.22.2
error[E0308]: mi...
New
In general, the book isn’t yet updated for Phoenix version 1.6. On page 18 of the book, the authors indicate that an auto generated of ro...
New
On page 78 the following code appears:
<%= link_to ‘Destroy’, product,
class: ‘hover:underline’,
method: :delete,
data: { confirm...
New
I’m a newbie to Rails 7 and have hit an issue with the bin/Dev script mentioned on pages 112-113.
Iteration A1 - Seeing the list of prod...
New
Hi, I’m working on the Chapter 8 of the book.
After I add add the point_offset, I’m still able to see acne:
In the image above, I re...
New
Title: Agile Web Development with Rails 7: (page 70)
I am running windows 11 pro with rails 7.0.3 and ruby 3.1.2p20 (2022-04-12 revision...
New
I am using Android Studio Chipmunk | 2021.2.1 Patch 2
Build #AI-212.5712.43.2112.8815526, built on July 10, 2022
Runtime version: 11.0....
New
From page 13:
On Python 3.7, you can install the libraries with pip by running these commands inside a Python venv using Visual Studio ...
New
Other popular topics
Let’s get real. As in really knowing—clearly and practically—what’s up with Phoenix LiveView.
What is it?
How does it work?
What can I ...
New
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
New
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting:
asdf install erlang 23.1.2
Configure failed.
checking ...
New
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me.
I think the Planck and the Preonic (o...
New
I am asking for any distro that only has the bare-bones to be able to get a shell in the server and then just install the packages as we ...
New
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
Hi folks,
I don’t know if I saw this here but, here’s a new programming language, called Roc
Reminds me a bit of Elm and thus Haskell. ...
New
We’ve talked about his book briefly here but it is quickly becoming obsolete - so he’s decided to create a series of 7 podcasts, the firs...
New
Author Spotlight: Mike Riley (@mriley)
This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s bo...
New
Author Spotlight: David Bryant Copeland (@davetron5000)
We’re so happy to bring you another Author Spotlight, a series where we sit d...
New
Latest in Pragprog
Latest (all)
Categories:
My Saved Portals
-
None saved yet
Popular Portals
- /elixir
- /opensuse
- /rust
- /kotlin
- /ruby
- /erlang
- /python
- /clojure
- /react
- /quarkus
- /go
- /vapor
- /v
- /react-native
- /wasm
- /security
- /django
- /nodejs
- /centos
- /haskell
- /rails
- /fable
- /gleam
- /swift
- /js
- /deno
- /assemblyscript
- /tailwind
- /laravel
- /symfony
- /phoenix
- /crystal
- /typescript
- /debian
- /adonisjs
- /julia
- /arch-linux
- /svelte
- /spring
- /preact
- /flutter
- /c-plus-plus
- /actix
- /java
- /angular
- /ocaml
- /zig
- /kubuntu
- /scala
- /zotonic
- /vim
- /rocky
- /lisp
- /html
- /keyboards
- /vuejs
- /nim
- /emacs
- /nerves
- /elm
Devtalk Sponsors
Practical resources that improve the lives of professional developers.
We build trusted fault-tolerant systems that scale to billions of users.
Catch errors, track performance, monitor hosts and more.
Enabling companies to succeed by building software people love.
Courses that'll move you from confusion to "Aha, now I get it!"