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.
0
votes
2answers
31 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. ...
3
votes
1answer
53 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
19 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 ...
-1
votes
0answers
34 views
How to avoid passing parameters through the call chain?
I am trying to write better code using Spark and Scala.
I have a driver program which creates the Spark Context and configures it and then calls on an executor class which handles the specific logic I ...
6
votes
0answers
50 views
4
votes
1answer
144 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
44 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
124 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
45 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
100 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
191 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
15 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
21 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
56 views
2
votes
1answer
58 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
112 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
63 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
66 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
88 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
52 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
66 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
56 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
44 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
55 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
30 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
45 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
74 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
73 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
275 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
224 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
179 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
83 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
121 views
4
votes
2answers
125 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 ...
10
votes
1answer
190 views
Scanner in Scala
I wanted to implement Java's Scanner in Scala. The goal for this class is to:
Implement a Scala collection interface (probably ...
4
votes
3answers
421 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
52 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:
...
4
votes
1answer
167 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
99 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
68 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 ...
6
votes
1answer
89 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
66 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
49 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
92 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
256 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 ...
