andre
Effective Haskell: Chapter 10 - directorySummaryWithMetrics (B9 - PDF version)
On p.386, we have the final version of directorySummaryWithMetrics.
When running the code, we see the histogram results with empty characters.
It looks like this
Histogram Data:
: 9091
: 59
: 23
: 1
: 2
: 59
: 12900
: 643147
: 20
: 22
: 563
: 6
: 666771
!: 1476
": 137317
#: 7367
...
The non-printable characters do not display. You can see the empty fields above ASCII value 20 (a total of 666771 spaces here).
Here are the last few lines of the function:
histogram <- readIORef histogramRef
putStrLn "Histogram Data:"
for_ (Map.toList histogram) $ \(letter, count) ->
putStrLn $ printf " %c: %d" letter count
displayMetrics metrics
I suggest to add a check using isControl.
import qualified Data.Char as Char (isControl)
...
histogram <- readIORef histogramRef
putStrLn "\n\nHistogram Data:" -- Added "\n\n"
for_ (Map.toList histogram) $ \(letter, count) ->
if Char.isControl letter then -- Added if .. then ...
putStrLn $ printf " %d: %d" letter count
else
putStrLn $ printf " %c: %d" letter count
displayMetrics metrics
–
Andre
Popular Pragmatic Bookshelf topics
The following is cross-posted from the original Ray Tracer Challenge forum, from a post by garfieldnate. I’m cross-posting it so that the...
New
Title: Hands-on Rust: question about get_component (page 295)
(feel free to respond. “You dug you’re own hole… good luck”)
I have somet...
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
Hi, I have just acquired Michael Fazio’s “Kotlin and Android Development” to learn about game programming for Android. I have a game in p...
New
When installing Cards as an editable package, I get the following error:
ERROR: File “setup.py” not found. Directory cannot be installe...
New
The allprojects block listed on page 245 produces the following error when syncing gradle:
“org.gradle.api.GradleScriptException: A prob...
New
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
New
@parrt
In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....
New
Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...
New
@mfazio23
Android Studio will not accept anything I do when trying to use the Transformations class, as described on pp. 140-141. Googl...
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
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
Rust is an exciting new programming language combining the power of C with memory safety, fearless concurrency, and productivity boosters...
New
This is going to be a long an frequently posted thread.
While talking to a friend of mine who has taken data structure and algorithm cou...
New
Author Spotlight
Erin Dees
@undees
Welcome to our new author spotlight! We had the pleasure of chatting with Erin Dees, co-author of ...
New
I have always used antique keyboards like Cherry MX 1800 or Cherry MX 8100 and almost always have modified the switches in some way, like...
New
Big O Notation can make your code faster by orders of magnitude. Get the hands-on info you need to master data structures and algorithms ...
New
Hello,
I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
This is cool!
DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON
We just witnessed something incredible: the largest open-s...
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
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /deno
- /kubuntu
- /arch-linux
- /nodejs
- /ubuntu
- /revery
- /spring
- /manjaro
- /julia
- /lua
- /diversity
- /markdown
- /v









