Questions tagged [scala]
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.
494 questions
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Evaluating an expression with shunting yard algorithm
I'm learning Scala and wrote a simple infix expression evaluator using the shunting yard algorithm. As opposed to the wikipedia example, this implementation evaluates the expression in place instead ...
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Created a Scala (Native-compatible) program that scores words in Scrabble. Any refactor tips?
As said in the title, I used Scala to make a simple little program that takes a formatted input string representing a word in Scrabble and spits out its score, including a message explaining where the ...
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Breaking a string expression in operator and operands
Requesting for a code review for a scala implementation.
Problem
Given an expression string made of numbers and operators +,-,/,* , break it in a list of Integer or ...
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Tic Tac Toe on the command line in Scala
This is my first Scala program, so I'd appreciate any feedback but especially feedback specific to Scala, for example situations where I could have utilised a feature better or where I've done ...
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Batching method implementation - Scala
I need to implement a function/method that operates on a sequence of values, and acts kind of like takeWhile, but with 2 differences, first, it doesn't act on a single element, it is performed on a ...
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Get tennis game's state using scala
I am developing a scala function called TennisGameStatus which returns the state of tennis games between two players.
To remind, here are the rules of tennis games :...
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Relational join of two datasets
Front Matter
I'm learning Scala and have not gotten used to functional programming and the language. I'm hoping a review of my naively implemented code can help me bridge my object-oriented ways to ...
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Extracting items from comma/semicolon-delimited strings, discarding parts after a hyphen
New Scala dev here. Is there a more idiomatic or efficient way to accomplish this in Scala?
Given a list of the following strings, I need to obtain the unique 'main parts' once any parts including ...
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Scala Parentheses Balancing in Functional Programming
I was working on the problem to check if the parenthesis are balanced using Scala.
Examples:
balance("(Hello (my) name is (StackOverflow))") -> ...
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Deserialize a binary tree breadth-first in functional programming
A while back, I answered this question on Stack Overflow that involved deserializing a binary tree breadth-first using functional programming (the question itself isn't relevant). I'd like to make ...
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Checking whether a graph is connected in an immutable way
I have this function at the moment
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Is My Function to Find Triplets in Scala running in O(N^2)
Given the classical problem to find triplets that sum to zero in an array. Is my Scala implementation correct and executed in O(N^2)? If yes, why? Can someone make a running time analysis.
What other ...
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Scala 3 Typeclass derivation using low-level mechanisms: The `Eq`-example
I've been playing around with this example from the Scala 3 documentation, and I noticed that certain things duplicate functionality already present in the standard API; In particular, the ...
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Efficiently calculate value of Pascal's Triangle using memoization and recursion
So reading about functional programming, applications to dynamic programming, and learning Scala. I figured I would try it out with a popular example, Pascal's Triangle, tests against known values ...
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Improving Mancala Game
https://www.mastersofgames.com/rules/mancala-rules.htm
I am trying to create a working Mancala Game in scala, Currently, I have 3 classes, Board, ...
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filtering element of one List from another in Scala with different tuple structure
I am trying to understand the best way to write this. This is part of my organization work so can't disclose it fully here like why such requirement. So Apologies for that.
I have ListA and ListB.
<...
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Find All Permutations of String in Scala
I created the following function, permutations, to produce all permutations of a List[A].
Example:
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Find Permutations of String in Scala
Given a smaller strings and a bigger string b, design an algorithm to find all permutations of the shorter string within the longer one.
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Keyword classification in Scala... simple? [closed]
I am pretty newbie in Scala, my background expertise is basically Java and Python, and I'd like to know your thoughts about this code snippet written in Scala to know if this is a "regular piece ...
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Group events close in time into sessions and assign unique session IDs
The following is a trimmed-down example of my actual code, but it suffices to show the algorithmic problem I'm trying to solve.
Given is a DataFrame with events, each with a user ID and a timestamp.
<...
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Stack Implementation in Scala
I would like to get feedback on my code for Stack implementation written in scala. What can be improved to make it more like scala code. What important helper functions am i missing?
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Concatenating optional strings in Scala
I have two optional strings, any of them can be None. I want to create their combination with a delimiter between them if they both exist.
I expect to be able to come with a more concise and nicer ...
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450
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Scala: drop elements in Sequence
Can I reduce the loop inside my method with map or is there a shorter implementation of this code that's dropping elements in sequence?
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Grading script in SCALA
The prompt is as follows: This script will use a text menu to give the
user options. The options will include the ability to add grades of different types as well
as an option to print the current ...
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Scala function to parse json with time fields to appropriate case classes. How can I write this better?
I have the below function which populates different time-related case classes based on what is present in the JSON input.
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SBT Helm plugin
Description
I've created simple SBT plugin which enables creating Helm Charts
The main reasons:
in Helm it is impossible to 'fetch' external files: https://github.com/helm/helm/issues/3276 which is ...
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Rewriting scala code in object-oriented style style to reduce repetitive use of similar functions
I need help in rewriting my code to be less repetitive. I am used to coding procedural and not object-oriented. My scala program is for Databricks.
how would you combine cmd 3 and 5 together? Does ...
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603
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Improving my Tic Tac Toe Solution in Scala
I'm relatively new to Scala and made a small TicTacToe in a functional Style.
Any improvement options would be highly appreciated.
There are some things which I am unsure of if they are made in an ...
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261
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Improvements, TicTacToe in Scala
I've just started my journey into functional programming and tried to implement a TicTacToe game Recursively without State in Scala.
What I dislike is the JOptionPane but I don't know if i can solve ...
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212
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Convolution function
I implemented the following function using the matrix object from breeze library. Basically it is just a glorified while loop.
The convolution there is extremely ...
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385
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argmax of List of Double
Here is my implementation of arg max in Scala. q_table_test.txt contains:
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Spark Scala: SQL rlike vs Custom UDF
I've a scenario where 10K+ regular expressions are stored in a table along with various other columns and this needs to be joined against an incoming dataset. Initially I was using "spark sql rlike" ...
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Compressing string in Scala, how to do this immutably?
I have a string "abbbbccdddd" and the function should return "a1b4c2d4".
This is what I have written in Scala.
Iterative-version
...
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Scala code to insert a row into Hbase
Below is a case class and a companion object with a method putRecord which adds a new row into Hbase using Put API. This code has some repetitive parts. Is there a ...
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How to make it more Scala compatible?
When you write a code in python code people always ask to make it more pythonic. I am not sure if there is a term for scala or not. However, I am pretty sure my following code use one or two scala ...
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Scala: Cumulative String Tokenisation
I'm trying to split an incoming stream of strings into cumulative tokens per line item using a function below,
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A better OOP way for solution
I am implementing a functionality in Scala to Copy files from one FileSystem to another ...
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A simple data class based on an existing collection (Scala)
I'm fairly new to Scala and I would like to learn it properly. My current task is to create a type to represent a heap, as seen in interpreters: a mapping from addresses in memory to values stored ...
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What is better to use for mapping value to Map of functions: tail recursion or foreach?
I want to map functions from my functions library (Map called as chain) to input string str. ...
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Clean up tags from a text
I need to generate random text for tests. I do that using alphanumeric characters and some special characters as well.
For some special cases, I cannot generate the random text with tags.
I have the ...
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Integrating caliban, ZIO and Akka
I created a small sample project using caliban, akka-persistence and ZIO. I'm not really happy with the wiring code:
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implementation of atoi in scala
I've implemented atoi function as described in leetcode problem string-to-integer-atoi.
I am looking for some feedback on writing this in a more scala native way ...
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generic implementation approaches for a recursive function
Let's take the famous fibonacci problem as an example but this is a generic problem. Also, taking scala as the language as it's rather feature-rich. I want to know which solution you'd prefer.
we all ...
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Scala graph coloring
i have solved this problem https://leetcode.com/problems/find-eventual-safe-states/submissions/
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Finite automaton library in Scala including subset construction and minimization
I built a scanner generator like flex or jflex in Scala for a class last year. Part of this project is a small library for handling and manipulating finite automata. It works completely as intended, ...
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Functional filter unique elements in sequence is not as good as imperative [closed]
Can you please help me fulfill the following?
Requirements:
Create an iterable with unique elements. Their order should be preserved:
a | b | a | c → a | b | c
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Bellman-Ford Implementation in Scala/Java
I think the part to get shortest path from the cost table got pretty messy. Also can use some tips on how to avoid the extra O(V+E) work checking all edges from source to dest after getting the cost ...
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668
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Perfect Number usage in higher order function
I am new to Scala.
I have been trying to complete an exercise where the ask was as follows:
// Write a function isPerfectNumber which takes integer input and returns String output.
// It finds if a ...
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Synchronous use of Mongo-Scala Driver
The Mongo-Scala Driver (v2.6) currently only supports asynchronous operations, although my use cases often seem to lend themselves well to synchronous reads. This may be to block downstream code ...
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Dotty 0.19 (Scala 3) features: contextual abstractions
tl;dr
I tried to write some as general and as feasible as possible code where entities are able to communicate with other entities of the same type or of different types, allowing for the recipient ...
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