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import scala.slick.lifted.CanBeQueryCondition
// optionally filter on a column with a supplied predicate
case class MaybeFilter[X, Y](val query: scala.slick.lifted.Query[X, Y]) {
  def filter[T,R:CanBeQueryCondition](data: Option[T])(f: T => X => R) = {
    data.map(v => MaybeFilter(query.filter(f(v)))).getOrElse(this)
  }
}

// example use case
import java.sql.Date

shankarshastri

Applied Functional Programming with Scala - Notes

Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

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apiVersion: v1
kind: Service
metadata:
  name: redis-service
spec:
  type: LoadBalancer
  selector:
    app: redis
  ports:
    - name: redis

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import java.io.ByteArrayOutputStream
import java.time.Duration
import java.util.concurrent.Executors
import java.util.{Properties, Timer, TimerTask, UUID}

import Models.{Message, SystemMessage, UserMessage, msgAvroSchema}
import com.sksamuel.avro4s.{AvroInputStream, AvroOutputStream, AvroSchema}
import org.apache.kafka.clients.consumer._
import org.apache.kafka.clients.producer._
import org.apache.kafka.common.errors.WakeupException

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How to setup Let's Encrypt for Nginx on Ubuntu 18.04 (including IPv6, HTTP/2 and A+ SLL rating)

---

Virtual hosts

Let's say you want to host domains first.com and second.com.

Create folders for their files:

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package akkahttptest

import akka.http.Http
import akka.stream.ActorFlowMaterializer
import akka.actor.ActorSystem
import akka.stream.scaladsl.{Sink, Source}
import akka.http.model._

object TestClient extends App {

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case class TrieNode[T](edgeList: Map[T, TrieNode[T]] = Map.empty[T, TrieNode[T]], isLeaf: Boolean = false,
                       isEntry: Boolean = false)

object TrieNode {
  def emptyTrieNode[T]: TrieNode[T] = {
    TrieNode[T]()
  }

  def newTrieNode[T](data: T): TrieNode[T] = {
    TrieNode[T](edgeList = Map[T, TrieNode[T]]((data, emptyTrieNode[T])))

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import scala.annotation.tailrec
import scala.collection.immutable.HashMap

case class TrieNode(h: HashMap[Char, TrieNode], isWord: Boolean = false)
object TrieNode {
  def empty = TrieNode(HashMap.empty)

  def buildTrieNode(s: List[Char], t: TrieNode = TrieNode.empty): TrieNode = {
    s match {
      case Nil => t.copy(isWord = true)

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import scala.annotation.tailrec
import scala.collection.mutable

case class MutableTrieNode(h: mutable.HashMap[Char, MutableTrieNode], isWord: Boolean = false)
object MutableTrieNode {
  def empty = MutableTrieNode(mutable.HashMap.empty)

  def buildTrieNode(s: List[Char], t: MutableTrieNode = MutableTrieNode.empty): MutableTrieNode = {
    s match {
      case Nil => t.copy(isWord = true)

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def editDistance(s1: String, s2: String): Int = {

  val s1Arr = s1.toCharArray
  val s2Arr = s2.toCharArray

  val mapOfEditDistance = scala.collection.mutable.HashMap.empty[(Int, Int), Int]

  def editDistanceHelperDP(i: Int, j: Int): Int = {
    mapOfEditDistance.getOrElseUpdate((i, j), if(i == -1) {
      mapOfEditDistance.update((i, j), j + 1)