geoand

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

geoand

fun <T> List<T>.collate(size: Int, step: Int = size): List<List<T>> {
    require(size >= 0) {"size must not be negative"}
    require(step <= size) {"step must be at most equal to size"}

    return collateRec(this, size, step, listOf())
}

private tailrec fun <T> collateRec(list : List<T>, size: Int, step: Int, accumulator: List<List<T>>) : List<List<T>> {
    if(list.isEmpty()) {
        return accumulator

geoand

fun <T, M> Iterable<T>.countBy(transformer: (T) -> M) : Map<M, Int> {
    val emptyMap = mapOf<M, Int>()
    return this.fold(emptyMap) {accumulator, item ->
        val transformedItem = transformer(item)

        accumulator + Pair(transformedItem, accumulator.getOrElse(transformedItem, {0}) + 1)
    }
}

geoand

/**
 * Method extension code
 */

fun <T1, T2> Collection<T1>.combine(other: Iterable<T2>): List<Pair<T1, T2>> {
    return combine(other, {thisItem: T1, otherItem: T2 -> Pair(thisItem, otherItem) })
}

fun <T1, T2, R> Collection<T1>.combine(other: Iterable<T2>, transformer: (thisItem: T1, otherItem:T2) -> R): List<R> {
    return this.flatMap { thisItem -> other.map { otherItem -> transformer(thisItem, otherItem) }}

geoand

import groovy.transform.TailRecursive
import groovy.transform.ToString

@ToString(includePackage = false)
class Node<T> {
    T data
    List<Node<T>> nodes = []
}

final builder = new ObjectGraphBuilder(classLoader: getClass().classLoader)

geoand

tailrec fun <T : Comparable<T>> binarySearch(list: List<T>, item: T, startIndex: Int = 0, endIndex: Int = list.size - 1): Int {
    if (endIndex < startIndex ) {
        return -1
    } else if (startIndex == endIndex) {
        return if (item == list[startIndex]) startIndex else -1
    } else if (endIndex == startIndex + 1) {
        if (list[startIndex] == item) {
            return startIndex
        }
        else if(list[endIndex] == item) {

geoand

def list = [1,4,9]

println subsets(list)

List<List<Integer>> subsets(List<Integer> list) {
    if(!list) {
        return [[]]
    }

    final List<List> directSubs = list.tail().collect {

geoand

tshark -c 50 -NnNC  -E header=y -Tfields -e col.Protocol -e ip.dst -e ip.dst_host -e tcp.dstport -e udp.dstport -f "host $(hostname --ip-address) and (tcp or udp) and not (port 53)"

geoand

@Grapes(
        @Grab(group='com.google.guava', module='guava', version='18.0')
)
import static com.google.common.collect.Sets.*


def first = ['a', 'b', 'c'] as Set

def second = ['b', 'c', 'd', 'e'] as Set