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.
5
votes
1answer
24 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
54 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
157 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
25 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
41 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 ...
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votes
2answers
76 views
2
votes
2answers
41 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
72 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
59 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
32 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
104 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
167 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
62 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
55 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
43 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
363 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
63 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
41 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
55 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
74 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
83 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
55 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
127 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
59 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
152 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
86 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
50 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
329 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
291 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
350 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?
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2
votes
2answers
102 views
Tail Recursive Fibonacci
Please critique my implementation of a tail-recursive method for generating the Fibonacci sequence:
...
1
vote
0answers
66 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
300 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
90 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
99 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
103 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 ...
4
votes
1answer
105 views
A simple “Tamagotchi” like game that uses math questions as food
I wrote a Tamagotchi-like game where to feed the pet, you do math questions instead of just pressing a button. It's persistent, in that on loading, it figures out long it's been since the last save, ...
6
votes
3answers
360 views
Checking for balanced parentheses
I wrote a method to check if each parenthesis in a string is closed. It should take into account the order in which a parenthesis is presented, e.g. "hello)goodbye(" should return false even though ...
7
votes
2answers
135 views
Scala BitSet implemented with Java BitSet, for use in Scala Enumerations to replace ValueSet
Due to a performance profiling hotspot detailed here, I implemented my own BitSet using Java's BitSet. This is intended to ...
14
votes
1answer
122 views
Oh ye beloved bejeweled
Before @bazola asked his recent question we chatted about it for a bit. I figured that I could try implementing something similar myself.
As I've heard that Scala has all the advantages of Java but ...
1
vote
1answer
88 views
Scala Case Classes
Please take a look at the following Scala program and give me suggestions for improvement. I'm sure there would be plenty. This is my very first Scala code, so please don't be frustrated because of ...
2
votes
3answers
246 views
A Cipher with 2 methods for encryption/decryption
I'd like advice on how this could be written more efficiently, idiomatically, or just anything that could be improved upon.
I'd also like to know if there's an alternative to my ...
1
vote
0answers
199 views
Idiomatic Scala for nested map/flatmap
Does anybody have an idea on how to make this code more idiomatic? I tried to use scalaz Traverse, but it didn't really help.
Given the types and method signatures:
...
12
votes
1answer
128 views
First four Project Euler in Scala
I was working on teaching myself some Scala and decided to tackle some Project Euler problems. The first four of these turned out to be one liners.
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