Scala is a general purpose programming language principally targeting the Java Virtual Machine. Designed to express common programming patterns in a concise, elegant, and type-safe way, it fuses both imperative and functional programming styles.
3
votes
0answers
19 views
Finding the most frequent words in Scala using Akka
I'm new to akka and would like to get some feedback on my first attempt. The code takes text from stdin and finds the top 10 most frequently occurring words.
Specifically, I would like to know
Is ...
2
votes
0answers
17 views
Frequency of words in all files of a directory using Future - Scala
I created a program to get frequency of word in all files in a directory using Future API
...
1
vote
0answers
11 views
Stronger Functor TypeClass
I'm working on arrow library for scala
I've come with some new typeclass, which looks like generalized Functor
...
0
votes
0answers
19 views
Object to YAML (and viceversa) conversion in Scala
In order to learn Scala, I'm writing a simple module that takes a Service object I defined and serializes it in YAML format.
This is the definition of my ...
2
votes
0answers
23 views
Immutable queue implementation in Scala
I created a queue in which we can perform Enqueue, Dequeue and Traversing in Scala.
...
1
vote
0answers
17 views
Avoid asInstanceOf in a type class implementation
With the help of SO I got my code working, but I think it still could be improved, in particular I do not like using asInstanceOf. Is there some way how to avoid ...
2
votes
1answer
25 views
List of Files in any Folder - Scala
I have written a code to count the number of files in a folder and if there are any folder inside folder it will count the files in that folder too.
...
8
votes
1answer
68 views
Scala implementation of @rolfl's integer-partitioning algorithm
While reviewing @Martijn's Distinct sums of integers (finding all combinations of positive integers that sum to a given number), I proposed the following solution:
...
2
votes
3answers
39 views
Producing uniform lists in Scala
When writing an answer to another question here, I came across the problem of producing lists of integers having a certain total and only consisting of a certain number and an optional rest. So for ...
4
votes
2answers
57 views
Functional translation of dice simulation
I have tried my hands at "functionalising" a toy problem I had: find the expected number of throws of a six sided die until all sides have been seen (the answer is 14.7)
My starting point is my ...
1
vote
1answer
21 views
Similar 2 classes in Scala need to refactoring
I am newbie in scala don't know how to refactor to make it better because currently it kinds of boring when read it.
I have 2 classes BidWinPostData and BidEventPostData.
They are kind similar the ...
0
votes
0answers
21 views
PBKDF2 and HMAC implementation in Scala
First of all: I know that rolling your own cryptographic functions is bad. The SHA256 implementation i use is from Bouncycastle, but i think both HMAC and PBKDF2 are not vulnerable to timing attacks ...
0
votes
2answers
44 views
Adding polynomials represented as maps
I'm using maps to represent a polynomial.
The key is the exponent and the value is the coefficient : Map(exp -> coef)
e.g. ...
7
votes
3answers
112 views
Distinct sums of integers
I need to get the distinct sums of naturals of a natural
What I came up with is:
...
1
vote
0answers
34 views
collect and parallelize in spark performance
the below code is working fine, but as this is new for me, please help to improve performance. as I have not included yet my complex logic but confused over collect and parallelize.
Aim is to collect ...
6
votes
0answers
60 views
4
votes
1answer
158 views
Solution to part 1 of Day 7 Advent of Code in Scala
Does someone want to review my solution to part 1 of Day 7 Advent of Code in Scala?
The assignment is here: http://adventofcode.com/day/7
Without repeating the whole text, in short:
Given a text file ...
4
votes
1answer
54 views
Return different type of response based on Accept header
I'm a novice to Scala and Akka-Http and am experimenting with Akka-Http for writing rest services. I have to return JSON or protobuf based on the Accept-Header.
...
3
votes
1answer
128 views
Handling HTTP requests and saving user to database
I am using Play Framework and Slick. In userController.scala I am handling HTTP post requests and sending to personRepository.scala. Is this controller and method written in the correct way?
...
4
votes
0answers
63 views
RandomForest multi-class classification
Below is the code I have for a RandomForest multiclass-classification model. I am reading from a CSV file and doing various transformations as seen in the code. I ...
0
votes
2answers
103 views
Divide list into n parts in scala [closed]
The problem is to divide a list into n parts according to a predicate. I found recursive solution but I am sure that a more elegant solution also exists.
...
14
votes
4answers
227 views
Ising Model - Atom Vibration Simulation in Scala
I am an experienced Java developer (12+ years) and have recently switched to Scala and I love it. However I feel not comfy yet and I have a feeling that I might use to many paradigms from the good old ...
1
vote
0answers
16 views
Handling state in actor
The following Actor monitors file by getting events from watchservice actor that sends a message to the actor and notifies for event (create,modify or delete), would love to know how I may improve ...
1
vote
0answers
23 views
Let user add rows to table
I'd like the user to be able to add rows to a table in my Play application written in Scala. The row is defined in a custom tag and makes use of Bootstrap via the plugin by Adrian Hurt.
My current ...
2
votes
1answer
69 views
2
votes
1answer
63 views
Scala code to print a Sudoku board and any possible unsolved values
I'm working through a Sudoku solver problem that I found at UPenn (no it's not my homework ;)). I'm a beginner at Scala, and I'm trying to write good functional code (not that this particular method ...
6
votes
2answers
116 views
String Calculator Kata in Scala
This is my solution of string calulator kata in scala(i'm new of tdd).
I'd like a general review of this.
String Calculator
Create a simple String calculator with a method int Add(string
...
3
votes
1answer
64 views
Generating the maximum number possible from an array
I have the following code in Scala as a solution to the problem:
Find the maximum number possible from the given Seq of Integers while keeping the individual numbers intact
e.g.
Seq(2,5,9,4) ...
1
vote
1answer
73 views
Early-termination foldLeft for Scala Streams
The foldRight and foldLeft methods for Scala Streams cannot terminate early, so here is my ...
3
votes
0answers
95 views
Parallel Merge Sort in Scala
I have been trying to implement parallel merge sort in Scala. My current implementation is about as fast as .sorted, but I have no idea what would be the right ...
3
votes
2answers
60 views
Bubble sort in Scala
I wanted to implement a bubble sort in Scala following the steps described in: http://www.bbc.co.uk/education/guides/z22wwmn/revision/3
...
3
votes
1answer
94 views
Scala Binary Search Tree
In an attempt to get deeper down into Scala, I decided to make a BST using as many interesting concepts as possible in order to explore everything Scala has to offer.
Taking inspiration from this ...
2
votes
1answer
62 views
A Scala script for beautify scientific notation strings from Excel
Excel renders scientific notation in the engineering fashion, e.g. “4.2E-5”. That’s OK, but when you are writing a scientific paper, it’s likely that you want it to look like this: “4.2×10⁻⁵”.
I have ...
2
votes
0answers
46 views
Console User Interface Framework
I've been learning Scala and I'd love to get your feedback in order to improve. As an exercise I made a simple framework for creating command-line user interfaces.
Gist
...
1
vote
1answer
47 views
Euler #25 Scala
I usually write Euler solutions in Javascript. On problems requiring very large integers I have decided to learn Scala and take advantage of BigInt. I wrote a ...
4
votes
1answer
69 views
Extending SeqLike - move an element to the front of the sequence
I wrote a method called bringToFront, which moves an element a to the first position of a sequence ...
1
vote
0answers
59 views
Design of Basic Dominion Game Cards [closed]
I thought it would be fun to implement the card game Dominion in Scala. I have implemented the basic card types and wanted to see if there was a better way to implement the card types. So far this is ...
0
votes
0answers
36 views
TrieMap based Simple Graph API
Looking for some feedback regarding elegance, about my code below implementing a simple graph API basing on scala.collection.concurrent.TrieMap.
Background:
I am ...
2
votes
1answer
101 views
Project Euler 4 The Functional Way
I'm learning Scala (and functional programming). Is there a better way to solve Euler problem 4 than either of these two solutions.
Euler 4
I like this array comprehension solution, but it wastes so ...
-1
votes
1answer
50 views
Why does this scala code only execute the last future when necessary? [closed]
From https://www.chrisstucchio.com/blog/2013/actors_vs_futures.html:
A very nice feature of Futures is that they are highly composable.
Consider the following problem. I want to return an HTTP ...
1
vote
0answers
76 views
Getting branches of a tree
Given a tree structure (in this example it a list of some nested group nodes), what is the best way to get all branches (branch = list of nodes from root to the leaf element)?
My solution (here root ...
6
votes
2answers
75 views
Text tokenizer example
Here is a partial example of a text tokenizer. I'm looking for ways to improve one particular line in this code:
...
5
votes
1answer
408 views
Binary tree implementation in Scala
This is my implementation of a binary tree in Scala. How can this be made better?
...
3
votes
1answer
47 views
Override values for overlapping objects between two scala lists
Let's say I have a bunch of Widget, where a Widget is
class Widget (sku: Int, label: String, name: String, description: String)
And I have 2 sources of Widgets: ...
11
votes
3answers
226 views
Kosaraju in Scala
I started coding in Scala some time ago, and also learning some fundamental algorithms in CS.
Here's a terribly slow implementation of Kosaraju algorithm to find strongly connected components in a ...
4
votes
1answer
55 views
A rename utility in Scala
I made a commandline tool for renaming files, similar to the rename command in Ubuntu. Here is the code:
...
3
votes
0answers
228 views
Combining pagination and non query grouping in Slick 3.0
I have the following tables:
val postTable = TableQuery[Posts]
val postTagTable = TableQuery[PostTags]
val tagTable = TableQuery[Tags]
One post can have multiple ...
-1
votes
2answers
95 views
Seq[Either[A, B]] => Either[A, Seq[B]] Function
I wrote a function of type Seq[Either[String,Int]] => Either[String, Seq[Int]]
...
3
votes
1answer
122 views
4
votes
2answers
141 views
Scala fraction addition
This just adds fractions. For example, if we have a text file with:
1/3
1/2
It will print:
5/6
I would love to hear some ...
