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.

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4
votes
2answers
248 views

Debounce in Scala

This is my attempt at implementing debounce in Scala without any 3rd party library. How can I improve the code/make it more idiomatic (and any bugs I might have missed)? ...
4
votes
1answer
30 views

Vigenère cipher encryption in Scala

I've worked out a functioning Vigenère encryption in Scala, and while it doesn't seem like my code is too hideous, I'm sure I could make it more functional and Scala-esque. Primarily, it seems like: ...
-1
votes
0answers
23 views

Cake Pattern Code? [on hold]

Given a general LoginService: ...
4
votes
1answer
133 views

White box input stream for creating test scenarios

I need to test a specialized input stream class that takes input from a TCP/IP network connection. I particularly need to ensure that the blocking and availability behavior is correct. To help me ...
5
votes
1answer
62 views

Fight simulator

I have been learning Scala for a couple months and want to get a more concrete understanding of proper oop practice. I find it difficult to optimally use traits, abstract classes and inheritance. ...
6
votes
1answer
46 views

Return the element of collection if the collection contains only one element

Recently I have found in my code several places where I was first gathering some solutions, and then continued processing them only if the solution was unique (solution collection contained only one ...
5
votes
0answers
35 views

Mapping a file system to a tree structure

I need to write a very basic file/directory browser. The data structure I'm using is pretty simple - a Node with an optional parent and children. Along with the data structure I also need a simple ...
6
votes
1answer
55 views

Equilibrium Index Implementation

I have come up with a solution to the equilibrium index problem with help from the answers off here: ...
5
votes
1answer
38 views

Simple substitution encryption with Scala

I've just started teaching myself Scala to get my feet wet with functional programming, and I'm messing with around with some classical cryptography. The following code produces monoalphabetic simple ...
4
votes
1answer
62 views

Count unique characters in a String and group the counts

The code counts the amount of unique characters that fit in the character set ACGT (stemming from nucleobases). We take a string as input that must contain only ...
3
votes
3answers
164 views

Find anagrams in a list

Write a program that, given a word and a list of possible anagrams, selects the correct sublist. Given "listen" and a list of candidates like ...
2
votes
1answer
30 views

Clean phone number

Program that cleans up user-entered phone numbers so that they can be sent SMS messages. The rules are as follows: If the phone number is less than 10 digits assume that it is bad number If the ...
4
votes
2answers
44 views

Count chars difference between two strings

Given two strings with the same length, we check how many chars on the same positions are different. For example: ABCD and ABBD should return 1. Here is a link to a gist with tests, to have a better ...
-2
votes
2answers
83 views

How to split long lines of code? [closed]

If I have a one liner method that looks like this: ...
2
votes
2answers
47 views

Count of words in a mutable Map

The function should get some text on input and return a map in a following format: ("word1" -> 1, "word2" -> 2 ...) The keys are words from text and the ...
6
votes
2answers
79 views

Implement the method “plus”

I'm implementing a plus method that should work this way: 1 plus 2 // 3 "a" plus "b" // "a and b = ab" Here is my implementation: ...
4
votes
1answer
68 views

Game boot to some operations every second

I am building game, like Ogame, or Ikariam where you can play with other users in real-time. You train some soldiers, and build some vehicles or buildings. Every building or vehicle has some level. If ...
4
votes
1answer
34 views

Filtering a phone number

I am learning Scala still and refactoring some old code. I was hoping the community here could give me pointers to fix this code up since there are some issues I have with it visually, but don't know ...
7
votes
1answer
107 views

Validation macro

I would like a review of a Scala validation library I am writing. For now we can focus on the regular expression component. The usage is described in RegexExample.scala There is an outline of the ...
5
votes
3answers
183 views

Replacing all occurrences in a String

I have a string like this : val content = "some_text{macro1}another_text{macro2}text" I want to replace the {macro1} and ...
5
votes
1answer
72 views

Safe cracker string with all combinations

Imagine a safe with a 4-digit code, and accepting a continuous stream of code entries, such that when the 4 digits are seen in the right sequence, the safe opens. Generate a short string that ...
4
votes
1answer
59 views

Find minimum number of coins (count and list of coins too)

For a given set of denominations, you are asked to find the minimum number of coins with which a given amount of money can be paid. Assume that you can use as many coins of a particular ...
4
votes
0answers
48 views

Selecting subset of size k using recursion

Sometimes I need to implement recursive algorithms that pass a certain state from one recursive call to another. For example, a greedy subset selection: we have a set of candidate objects, and we ...
7
votes
3answers
415 views

n-digit Verification Code Generator

This is a verification code generator, which generates n-digit numeric strings. (code can be 0000, so I chose String as a return ...
5
votes
2answers
64 views

Simple load balancer model in Scala

For one of my cases in algorithms I am required to create a model of a load balancer model for multiple processors. Lately I became interested in Scala so I decided that it would be great to create ...
2
votes
3answers
42 views

Tail-Recursion to get a Map of word counts

I want to read a file and store the number of occurrences of each word in a Map, using tail recursion. I came up with the following; it seems to work; does it look like it's right? ...
1
vote
1answer
64 views

Graphs processing in Scala

I've just started to learn Scala and decided to implement small graph library to train. Here is the basic version, that describes graph and nodes structure and also provides implementation of ...
2
votes
1answer
98 views

Playframework (Scala) custom exception handling

I am using play framework with scala and here is a scenario on which I would like to have your opinion. Let's say I have 2 ...
2
votes
0answers
27 views

Functional, Loaner-Like Pattern For Consuming SQS Queues, Deleting Queue Items On Success

My program fetches input from a RabbitMQ or Amazaon SQS-like queue. There is not always input available in the queue. If a message is available, it triggers work. If that work is successful, ...
2
votes
1answer
92 views

Memoization of Fibonacci using generic Int => Int helper

I'm trying to understand memoization using Scala. I took the Fibonacci sequence as an example because of the high cost of recursively computing numbers in the sequence without memoization. ...
3
votes
1answer
56 views

Random Plinko path using functional programming style

In order to learn both scala and functional programming, I've been rewriting the projects from my introductory CS class in scala. One of the projects was a plinko game, where the user picks a slot to ...
11
votes
2answers
132 views

Converting imperative style user input menu to functional programming style

I am currently trying to teach myself scala by rewriting projects from my intro CS class, which was taught in C++. In addition to just learning the syntax I am trying to gain understanding of how ...
3
votes
1answer
48 views

Returning preferences

I have a function that returns some preferences, but first I have to do some checks to see whether the user is authorised to read them. I'm still not happy with the result (the match is a bit ugly). ...
1
vote
1answer
61 views

File-to-fully qualified class name function

My instincts are telling me a seasoned Scala programmer will find my code less than optimal. As will no doubt be obvious, I'm a Java guy who has just started in with Scala. Is there a more ...
1
vote
0answers
36 views

NonEmptySortedSet implementation

I'm looking for feedback specifically about what I might add to this to make it more usable or general, especially with regard to scala collection traits to implement. ...
1
vote
1answer
177 views

Extracting tuples from Excel sheet

My code have too much nested option processing which makes it ugly. But it has an advantage it has no side effect and typesafe. ...
10
votes
2answers
89 views

Test runner for Scala problems

I'm learning Scala and could use another set of eyes on the code below. I'm creating a test runner for the 99 scala problems set. I figure between actually solving the problems and working through the ...
1
vote
0answers
55 views

Using Java's Fork/Join library from Scala

I am a newbie trying to learn some Java and I am reading prof. Dan Grossman's introductory lecture notes on parallel and concurrent algorithms. I wrote a version of a divide-and-conquer algorithm for ...
3
votes
2answers
335 views

BFS Maze Solver in Scala

I recently got a Scala developer position, so I'd like to get more comfortable with Scala on my own. Here is a maze solver that I wrote (previously in other languages) that I translated to Scala. Any ...
3
votes
1answer
22 views

Gathering response from a pagable service

I'm wondering how this code could be improved. I especially don't like the use of mutable Buffer but not sure what the best way to get it out cleanly. ...
1
vote
0answers
331 views

Scala TryWith that closes resources automatically

I'm quite new to Scala and was surprised that there doesn't seem to be anything like Java's try-with-resources block. So of course I wrote my own little construct. Is there anything I could improve? ...
2
votes
1answer
394 views

Async Controller Play 2.3

Is this example the correct way of writing an Async controller end point in Scala using Play 2.3? ...
2
votes
2answers
109 views

Tail Recursive Fibonacci

Please critique my implementation of a tail-recursive method for generating the Fibonacci sequence: ...
1
vote
0answers
74 views

A Timer Construct to Simplify Timing Blocks of Code

This is fairly simple, so I'm just looking for ideas on anything that can be cleaned up, places it can be extended, and suggestions regarding style/naming (I'm terrible at naming). It allows you to ...
16
votes
2answers
328 views

API for looking up Japanese postal code

Most of my experience is in Python, Java and embedded C, and I need to learn Scala and Play for a new job. As an exercise, I decided to create a very simple API for looking up area by postal code, ...
1
vote
0answers
100 views

A Simple Thread Pool in Scala

I wrote the following that spawns n threads, uses them to process a queue of jobs, then returns a result. As well as any general suggestions, I'd like feedback on the following: How safe is ...
0
votes
0answers
24 views

Gathering emails, phones, URIs, and tag related to a room

I've made a strange method with multiples conditionals, creating a lot of Lists and I was wondering if I could write it in a better and more legible way. ...
4
votes
2answers
100 views

“Functionalizing” this tree walking method and cleaning it up

I have a MessageTree class that represents a binary tree of negative/positive. I'm looking to improve my walkTree method and ...
2
votes
2answers
77 views

List.containsSlice

In an effort to strengthen my functional programming, I'm reading Functional Programming in Scala. One of the assignments is to implement a function that does the same operation as ...
2
votes
3answers
107 views

Refactor jaccard similarity the “Scala way”

I'm trying to pick Scala up. This is a simple heuristic that checks a similarity value between two sets. I've done this a million times in Java or Python. The function works, but I'm certain I am not ...