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.
-4
votes
0answers
10 views
Scala spark add new column rdd containing matching values [duplicate]
I am a beginner in spark Scala . Given rdd1 and rdd2
...
-4
votes
0answers
23 views
Processing data spark scala function [on hold]
I am a beginner in spark Scala .
Given rdd1 and rdd2
...
2
votes
1answer
41 views
Print Trace Debugger
See my Scala print trace debugger. This project is used for lightweight debugging sort of like the Haskell Debug.Trace module. The README, the documentation, and the test cases need work.
To test it ...
3
votes
0answers
21 views
Determining the HTTP status code to return for a request
I have a piece of code that I would like to refactor but can't figure how to do it. This is a method from a Play controller where I have to verify many precondition and respond different status for ...
2
votes
0answers
35 views
Needleman Wunsch algorithm in Scala
The Needleman–Wunsch algorithm is an algorithm used in bioinformatics to align protein or nucleotide sequences.
Here is an implementation in Scala:
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1
vote
2answers
94 views
4
votes
2answers
73 views
Limit HTTP request rate for spray/akka-http
I want to limit the request rate in a spray/akka-http route. I'm not an expert with both scala and spray/akka but learning. So I came up with the following custom directive:
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3
votes
0answers
55 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
24 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
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1
vote
0answers
20 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
23 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
36 views
Immutable queue implementation in Scala
I created a queue in which we can perform Enqueue, Dequeue and Traversing in Scala.
...
1
vote
1answer
27 views
Implicit type class for updating maps
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
33 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
77 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
42 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
64 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
22 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
24 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
45 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
116 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
43 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
67 views
4
votes
1answer
162 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
65 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
130 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
74 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
106 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.
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14
votes
4answers
234 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
19 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
25 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
90 views
2
votes
1answer
65 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
121 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
67 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
86 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
100 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
71 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
103 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
74 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�?��?�”.
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
50 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
73 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
46 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
53 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
79 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
543 views
Binary tree implementation in Scala
This is my implementation of a binary tree in Scala. How can this be made better?
...
