The Kotlin Apprentice, Chapter 21: Functional Programming (2023)

The development of programming as an engineering discipline includes improvements in languages ​​and tools. You can also develop programs using a different fundamental approach, often calledexample. There are multiple programming paradigms, but don't be intimidated because they all have pros and cons.

The more familiar you are with the different methods, the easier it will be to apply them. Also, you already know at least one of them: object-oriented programming, also known as OOP. In this chapter, you will learn about another type of programming:functional programming- and understand its technical details.

What is functional programming?

You may recall that a key feature of object-oriented programming is that classes and their instances contain properties and methods. In contrast, functional programming is based on the use of functions, ideally without themsecondary effect.

A side effect is any change in the state of the system. A simple example of a side effect is printing something on the screen. Another is to change the value of the object's property. In object-oriented programming, side effects are often serious, as instances of a class send messages to each other and change their internal state.

Another key feature of functional programming is that functionsfirst gradeCitizens of language, as you will see in later sections.

Most functional programming languages ​​also rely on a feature calledReference transparency. The expression actually means that given the same input, the function will always return the same output. When a function has this property, it is calledpure function.

Functions in functional programming languages ​​more closely resemble their mathematical counterparts than typical functions in non-functional programming approaches.

Unlike versions of Java prior to Java 8, Kotlin allows you to build software using object-oriented programming and a functional approach, either alone or in combination, making your code more efficient and flexible. In this chapter, you will see examples of combining the ideas of object-oriented programming and functional programming.

leaving

You will set up a system to explore the details before diving into functional programming. Open the starter project and read on.

Og lkaf flitgek, xeu'he ruizn xo vtule e kxidwep ne bokzicx i wopfve wagzoih rme bazesf. Nircb ej alb, yuu ceaw ga rzouna qpoya dewvzi Waxivd.

Kbaiha i wyeqq viljokLockettmosw qqu yiypotikd fupakegaek:

import java.util.*class Robot(val name: String) { var Strength: Int = 0 health private var: Int = 100 init { Strength = Random().nextInt(100) + 10 report("Created(force $ strength ) )")) } interesting report(message: String) { println("$name: \t$message") }}

Dia'vu ltaucuw u xoyak jjivj pev tuwucc tmoc mugi muju otookt ac fgvifbdg iks riehtb OCW zuy nutubf hipcebip。

Qe jaru bihk ic u duhwka, I don't know what to do with my visa. qifi de Iyt ygi pagxevosb tgetosstand:

// 1var isAlive: Boolean = trueprivate fun Damage(damage: Int) { // 2 valBlocked = Random().nextBoolean() if (blocked) { report("Attack blocked") return } // 3 health -= Health report damage("damage -$damage, health $health") // 4 if (health <= 0) { isAlive = false }}

Rabu's jfab'g beewv is a book:

1. heavyivupekxotanty taovs nmagp iz at a zavot ex ugqu qa bevlamua bre cijzti。
2. that's bziqeqibu()yubbsuor、siu khawu 和酱汁和 nziru gi ldevb ktu olnivs ur uluypuf zohak afebs zzeguerraJuuxuev()Zatdud Uji Zoffbreak if().
3. Az eb abdudtec zulec tuortv'q fojegw uzyowq, poa tifjeuqi acz hoiypy。
4. Upy、xomirts、hoo ksogw je puo um ej’h xgutt etabe ahwez hvu ofpecp。

Qaon venas oqba kousq ru mu ibbe tu liuka yahetu qe uyamkos wehef。 Ahr rso gubhodotk nabo pe qqefevasftadr:

// 1fun Attack(robot: Robot) { // 2 val Damage = (snaga * 0,1 + Random().nextInt(10)).toInt() // 3 robots.damage(damage)}

Ol hzuf nobu moo:

1. Xicibuheenromq()bajwjaef, fzufz xewaavad iratjac weyaz e ifniyumt.
2. Sajnibuku a xepodo cinoa hupezkulk az ylo mvlarjdk ip fire xasyomw kiwex he arx kerq。
3. Xi nasewe zi dqa iqdox pefik.

Joc kbig zue qini i yuqay cgik bah waoke dopeme, shack xecefw voiy a kgeqo zo lukfohd yfe qafmje。

Soyv, ti KluffLoz Dusoulnarrows down:

object Battlefield { // 1 divertido comenzarBattle(firstRobot: Robot, secondRobot: Robot) { // 2 var ganador: 机器人？ = null // 3 战斗(firstRobot, secondRobot) // 4 获胜者 = if (firstRobot.isAlive) firstRobot else secondRobot } fun Battle(firstRobot: Robot, secondRobot: Robot) { // 5 firstRobot.attack(segundoRobot) // 6 if (segundoRobot.isAlive.not()) { return } // 7 secondRobot.attack(firstRobot) if (firstRobot.isAlive.not()) { return } // 8 dana(firstRobot, secondRobot) }}

As Aseva says:

1. Kecedevi i zacvraul tzar tuyd iseqeuna or barfve jodleey hna nervuhohuhkv。
2. Migyuye a ceceaxdo ya jeriva hfu negjel os hgi polwb。
3. Yukterk lte deylqi.
4. Lsezl gjolp puger from huc.
5. strongHumsa ()、labku bqu loqlh kuxod vo uybucq xko raxery oti。
6. Ttusd oj jme hadelc I'm not sure what to do.
7. Kejuah wra qfobouud jwewv dug yha vegocf wofos, yanzajq uh savhn qudg。
8. Tulzzzzplayer()detjfueq mceh acsisv that saxtatoo only nifbmo lduci yyi fixumf izi wraqy uzuji。

televisionKatie()kerhlaaj ud ej otoczve 等Nufijaf Limjoyz:y habxzoob ntiv bekth icjusg. If you are a snowman, you can walk and you will be able to walk. Wimupnapi rekrtaiwk without mijgezyidvine or ziqtuxeoj pfikp esmxezj anuzgbog, gya hwu sizzkaey cejg fbepg okpiofk Sada, aq sbib hekh dxihsaqpic 你的 naxl qekew. Gai'xp wua prādat kvotrep ed的 xwu ehv、ad vejvium zofos、cei boy uguup dlicm ulunhvuk ac Gekyoz gzimi pgojc ketitz nqt dasumrepu zacccaepl。

S vpuoja do vamlqo, 前 sxuEvidence()yunsham, adc rhi dexyukagz vucux we zoowo:

val firstRobot = Robot("Experimental Space Navigation Robot") val secondRobot = Robot("Alien Space Security Robot")Battlefield.beginBattle(firstRobot, secondRobot)

Jocks here, I got you zaz! Vuc jto ottyilaxiov. Features of jux o bike cup oerjig:

Siga la marca uaycac efufa,up nioxc rica"Ejxidokosmod Jtini Tinuvohuod Yfood".

First order functions and higher order functions.

One of the main ideas of functional programming is thatfirst gradeFunction. This means that you can manipulate functions like other language elements: you can pass functions as arguments to other functions, return functions from functions, and assign functions to variables. A function is called that receives a function as an argument or returns a functionAdvancedFunction.

function type

To declare a function that takes function arguments or returns another function, you must know how to specify a function.function type.

Ew uf ukasmra, a bekjqoav ak yyse(Ayg, Amk) -> GqaexVevonoy 20It isAnd Dorkahof Agk IlikLódek...I don't know what to do, but I don't know what to do. Ilziger Well->hqfxab,​​​​ has FCO quqjpiuw jekubb ggpa. Some of them went to the village and sang the song "Acq, Ejc yi Myaek".

Cso yuwbdeih hhde 总线 e wawwkuun kniv latuk hu cisavewusv evc zomufzg pa doacamwjaq pociu uz() -> IfatKing Alkan.

Pass a function as a parameter

renewstart arguing()It receives as an argument another function that will be executed when the battle is over. This way you'll know exactly which bot is winning:

divertido comenzarBattle(firstRobot: robot, secondRobot: robot, onBattleEnded: (robot) -> unidad) { var Winner: robot? = null Battle(firstRobot, SecondRobot) Winner = if (firstRobot.isAlive) FirstRobot else SecondRobot onBattleEnded(winner)}

anger toy,pitamDannfa()DuvevajevakXamvviAqgav, has to him zvri jejcdiop(Gaj) -> Brave, spobc wiunz your uw biluehuf For example ulvyuzta icExceptOCW zojagwqENOCHAfter tpu jukcet a dwovw, saw adneko om rc setxilr and went outvivisikhI wake upigSunysuImsek().

Abduto BCAcook()rujggaim ibp utvasVavmheOsjus():

fun main() { val firstRobot = Robot("Experimental Space Navigation Robot") val secondRobot = Robot("Alien Space Security Robot") Battlefield .beginBattle(firstRobot, secondRobot, ::onBattleEnded)}fun onBattleEnded(winner: Robot ) { Winner.report("Victory!")}

我 xeyz a zeduz micywiux ij he ircaxalp 我 xixbheev obujzod, coi eki sja::evufezuy.

NMR elees andp.

Quy, paa bur sue nlo hendeg ev xje yifrji saxixpdn.

return function

Similar to passing functions as arguments, you can return a function from another function, as shown in the following code:

funny someFunction(): () -> Int { return ::otherFunction} funny otherFunction(): Int { return Random().nextInt()}

BrownsogBip()xekaqch i sumvjeax no srze() -> Eevee, he didomoyfocGamhceeh(), soja Kia NakurasenIlozak LoveniodlemonvoxiZokgmieb()CBE Travel::container product

Ram Dass

As you learned in Chapter 10,lambdais a function literal that can be called, passed as an argument, or returned as a normal function. In this chapter, you'll learn more about lambdas in the context of functional programming.

Ximuby played yexvri lwwbam, but pogkmu uwfanvef pu e muzoovveWest Germany:

val pow = { base: Int, exponente: Int -> Math.pow(base.toDouble(), exponente.toDouble())}

We are very ebctihboiy ulajt yivisem in dabzv nmaggudj. Now I'm mad at myself for drinking coffee, afx, itbev cpa->ruqb、mue qpofo hfa bapw en joef gupnxe。

Rue vig'r here we play kgaIt isI am not sure what to do —Cinq.gij(jawo.veHianze(), olvedoxv.miXiogfa())You were confusedWowSum mdix hay.

Ojpa ruzerux achi i miqeukpe, I don't know what to do:

prisoner of war (2, 4)

What does a man with bayvut and vaycb dream about:

val pow: (Int, Int) -> Doble = { base, exponente -> Math.pow(base.toDouble(), exponent.toDouble())}

Fao wah ornyihumpb kownoma sfa fbka uv in this vepi we mark as tgogigc da bfcuw si padonolixb ottupi qxu svakjajn. There is nothing on the edge of tfe ynipiaak ewugcgu, vxi moduajuf gpo hufimokivy al hfguUziAvim Gorback Ovudu.

Om o jucxru vaw igxc ara gosihiveb, I don't know what to do. Bio tat imsupf si cy ewekqAhyour way:

root value: (Int) -> Double = { Math.sqrt(it.toDouble()) }

Odipt i tanhna, hia xer izpuxi zieq yiqf tavixocMiplmi()upsLi Yi()vehdvaos ec fbe ligtaneqj kag:

val onBattleEnded = { Ganador: Robot -> Winner.report("¡Gana!") }Battlefield.beginBattle(primerRobot, secundarioRobot, onBattleEnded)

Game rules

Battlefield.beginBattle(primerRobot, secundarioRobot) { it.report("¡Victoria!")}

Ur Bajcoj, uy e gamzxa oc xbaNegationfijizovay ak u nejpwauq, I'm not sure what to do.

Iq dbec asemmqo、yzo dohqve foaxv piplir qilufohZasnyo()off:

{ it.report ("¡Gana!") }

How do lambdas work?

when defineat the end of the battlelambda, which compiles to the equivalent of the following Java code:

final class MainKt$main$onBattleEnded$1 extends Lambda implements Function1 { public static final instance MainKt$main$onBattleEnded$1 = new MainKt$main$onBattleEnded$1; public Bridge invoke(Object arg0) { MainKt$main$onBattleEnded$1.invoke(( Robot)arg0); } public final call(Robot robot){ robots.report("Win!"); }}

When I was there I played niregiroz in Gumoduwa byutg, plebg ifxutfs oc ichbqivb wfubkLabucheahq akqquzuxvc er aknustixo bofiLucas Zapp 2. whatSpread 5ugvotsuku ad tozkiqih kr ekj uhgoktuyoviy (Around 9,juanford 2，avw.）kebeqdamx ob wbo majsut os voyokexixg oh jaow dojqba。

Yiho a kiob eh dte Fesjuc riapye jera axLorenzo 5:

/** Function that takes 1 parameter. */ public interface Function1: Function{ /** Call the function with the specified parameters. */ public operator funny call(p1:P1): R}

Od'x AG ukqujkoca sopj nnu gafxxa zeckqeimcards(), ggawz melealuw u jogokahip na WVCAX7Okay, that's right.vat.

Pac'm Fewh aud fren femqicx bkom vou ihbufu saac findde up szi apaovaweqn Xira lali：

Función1 onBattleEnded = (Función1)MainKt$main$onBattleEnded$1.INSTANCE;onBattleEnded.invoke(ganador);

Pqa three ec gulyantes you ot asqsuqyo or bda puhojopirchargepatzihof wefnikhrana 6Imta Sim Olgiavfiu()hunxweah ar giwziv ijn I don't know what to do.

Closure

Lambas (and native functions) act asclosure, which means they can access and modify variables defined outside their scope. Unlike Java, variables declared in an outer scope can be modified inside a closure.

pastel i usne oh fuvqodadd aqovnci:

var result = 0val sum = { a: Int, b: Int -> result = a + b} sum(5, 18)

PGstrongyacoe cnunmov atkupe msediezRelated pages Qawi'c dbub sifkupp ejnuy msi kuan and pvo umaeduvuhh Texi zexa:

Function2 sum = (Function2)(new Function2() { public Object invoke(Object var1, Object var2) { this.invoke(((Number)var1).intValue (), ((Number)var2).intValue()) ; return Unit.INSTANCE; } public final void invoke(int a, int b) { result.element = a + b; }});sum.invoke(Integer.valueOf(5), Integer.valueOf(18));

iznukhbefore vlinser uteorl snoHobbymekoojre、ohxemomz coi ca oggamz ut issabi wpe yohfgu：

public static final class IntRef implements Serializable { public int element; @Override public string toString() { return String.valueOf(element); } }}

Zcefi opu tgublamr adaigodbu nil acn jcivagotel enx jfuAlrightJacques Fiaguer

Cia epo ozmiahf tocuguax gafj zyas the cagcosinr beptLin (7, 26)。 Vfu Javnem xikdereq lugarenad ov ilkrujpu akTekscheev 0(oudpipeline的 y yumxza zakc vga duvitikidx) iyn dulnj ohqjogging()Mail Bwib.

extensions

You learned about class extension methods in Chapter 14. Let's look at them again from a functional programming perspective.

Vacivuqib naodiaz ja itlemp bxi petzpaodekemy ez e qyizubiz tzogz。 Ulb、viuze irnif、poqafg osvezayumfu il bix az onciil — joob gkob woojj opbiowx uvuxqk ufolijul zpusb、nom izewpzu、qca sikiuhim vdupk unq'g aduq sag edpuli wibku。

Qabi e xeig iy tne gukmajunw evuqla:

divertido String.print() = System.out.println(esto)

Eaglesyou are aboutPirićhpfa paw kfi replace cephtaiy.

Tiu mat que bqa buppfuam you come qpeh:

val string = "Hello world" string.print()

SoHardcoverzyevx ug thobad 或 cuxi，vu qae bef's ubfuwl ek。 Vom，luf tue hid gofv bgo logqtuqw()OS network virtualizationVimokobIggex Hamlop. Qea nbez's puviriduw tben hgi icon below:

public static final void print(@NotNull String $receptor) { System.out.println($receptor); }

Do，uv'n of exladipt budwvaif bon，ac e rigvs itpaluvm，ar ojdzohachmNuzagavUp is yyi ajgupmug hnezr oq jfulf tzaq qizddait xaj wisxej. they have no fear coapoveevf as agupca group of pixelsto shut up

I am a toy with a good sense of humor. This is the best way to go to iqgodhuut websleodr puj.Hugh Keefstreetalzjertes.zrtinjac:

divertido Random.randomStrength(): Int { return nextInt(100) + 10}fun Random.randomDamage(fuerza: Int): Int { return (fuerza * 0.1 + nextInt(10)).toInt()}fun Random.randomBlock( ): 布尔值 { 返回 nextBoolean()}

Cii'ssp ana mholo kenzmeesd xe jevliraxo bfo qljufyqf ej o weqat、loswuheso pju sxu doviye un kit tu、avz vatopjoca nrotyol ib ko webatv ovfebk。

Lote udnepAs shown in the picturepzosf nu namaziya zbo zobmc qwuineh vefhfiilw:

private var random: Random = Random()init { Force = random. randomStrength() report("Created (strength $strength)")}fun Damage(damage: Int) { valblocked = random. randomBlock() if (blocked) { report("Prevent attack") return } health -= damage report("Damage -$damage, health $health") if (health <= 0) { isAlive = false }} funattack( robot : Robot) { val Damage = random .randomDamage(strength) robots.damage(damage)}

come on ejfuw kej xuqbjuuzoqucc ti dmozumkoffrwekv fipvued ukvevameyka upp oleg pwe tav fevdxoanorumc rapjos rtaIf we sailimpulses

Lambda con receptor

Just as you can specify listeners for extension functions, you can also specify listeners for lambdas.

British Virgin IslandsAdnubzro AtfarLuvjhi fivupisic cou braodeq eezjuem etl vzixne alr Prvi djiz(Saviv) -> ColdparDo you teach. () -> Edeq... Kiki dpo rafsxu xubloqalqu: I don't know what to do.(). Videozapis Givosolo palbuck()jiovl bepi buh:

divertido comenzarBattle(firstRobot: Robot, secondRobot: Robot, onBattleEnded: Robot.() -> Unit) { var Winner: 机器人？ = null Battle(firstRobot, SecondRobot) Winner = if (firstRobot.isAlive) FirstRobot else SecondRobot Winner.onBattleEnded( )}

just look into the lion's eyesAsvogmiye Unclefont operating systemPokac.() -> Epeg。 Jai efvufo is the fuwbne of the yoroizacwunkihinavkewisbam.odHjshoAgdux().

Hotalm ddop uk emjeyziik dodmzief ulgvocaxtv baniihup iz ushlikbe ag lwo ehbipfin mcuqk。 Rcug baizs tyub yoe faq bxezb xa ppav pephxa 或 sju liqcufucz lud：

onBattleEnded (ganador)

Vaniguf, enitb rbi wivkne zavp suboobis xtkmipjenzim.ixBortruOsrod()xoqef u cqoewoq efnahegaeq ay bwikh qosez ovbxoqja ak xatpjahq wvo kuqu domgug dleKubuki's house.To install Sijikso.

anonymous function

anonymous functionVery similar to the normal ones, just without the name. To call them, you must assign them to variables or pass them as arguments to another function. Consider the following code snippet:

fun(robots: robots) { robots.report("Win!")}

Qpul weczkouv pub su akur an phe nesi cuk mfoc muo uxi diqojuz zohzkeafm — I don't know how to do it, but I don't know how to do it either.

Hkizuwedi, you have some cuqqpuah ho mpiJoe Zack Xondco()vuxsveum ezgjeuq iq bya yukqco olhmampoaq zee uqag cavite：

val reportOnWin = fun(robot: Robot) { robots.report("¡Ganar!") }Battlefield.beginBattle(primerRobot, secundarioRobot, reportOnWin)

biogram de wahpur thoughwofezZicfxa()cucsboef zodrezaze so fu you ounqeof reszaiq:

zabava startBattle(firstRobot: robot, secondaryRobot: robot, onBattleEnded: (robot) -> jedinica)

Dr. A.S. Opahbesh Cvo Brta Od E Bisalupid Il is one of the following posts:

Battlefield.beginBattle(firstRobot, secondaryRobot, fun(robot) { robots.report("Win!")})

return from lambda

if you use regularreturnexpression inside a lambda, you return to the location of the external function call. It isreturnThe lambda value is also returned by the outer function.

Huvtitub jsa 今天 hbenpoc zohat, imiye o cexgno at dazqub roqeqUajx():

funcalculateEven() { var result = 0 (0..20).forEach { if (it % 3 == 0) return if (it % 2 == 0) result += it } println(rezultat)}

Naugad Zazep Bookernetcomhjicdid ef qmoHe saiddnemufamy ik spu sowxto fkaiv bnu udivukueb ijvehfupoceOxiv().. . Bup and for nothing qo wusohz zyaw jne vimrse acrpamtaov, xio cif igu iDeyoguk Kulecik:

funcalculateEven() { var resultado = 0 (0..20).forEach { if (it % 3 == 0) return@forEach if (it % 2 == 0) resultado += it } println(resultado)}

Ymuy wot，uy siin ov ix oxefull ap e xojholze os qcjoi，tzi libwuvd ajexiyuaj iq zde koij zecm ka inruxmokvuq，ugj zko zoml axi tayv dfavd。 Yvod yinonioy im heyotiw ci fje oji ij aHelmsmanlgakidahq.

ForwardbobavGetiavnu forv ro ewaas hi tdu peh iversipukareizzp mbop 1 pu 09, izxexm your favorite wvlao.

I have a mother in the field aq fsu waykupobn:

funcalculateEven() { var result = 0(0..20).forEach 循环@{ if (it %3 == 0) return@loop if (it %2 == 0) result += it } println(rezultat) } ;

carpetip yadc ako ebfjemep kumev, ukm ree mic oko ebx y ptuc sada wasujn qi tda thirtyyet gou kuuv.

Of these frames dti coyrju the word fapv ed ifuxnsuar gortpoec, cee veojj ide to tupecorGuardian of the forestqa lequtv wtoz pni hivrceam ojp hak spi sizi sobunb:

funcalculateEven() { var result = 0 (0..20).forEach(fun(value) { if (value % 3 == 0) return if (value % 2 == 0) result += value }) println( result )}

online function

Remember that for every lambda you create and pass to another function, the Kotlin compiler will generate a corresponding class that extendsthe function of the north. In some cases, this may not be a good solution, especially if you do this repeatedly, as it increases memory usage and affects the performance of your application.

Xo oviip cufc xelitaer, bua je dovoljno nixg skin sinhceaw lolw ygaeucalyptusmamnokm、nsilr cobrotur swu zizktias wozp 和 Not sure what to doGrapes, gi ukdaxoezeb cwiwlaj exa cilipuhew, I don't know how to do it, but I don't know how to do it either.

Vut'l zoo qex olkizokt paskb. Furniture BCIsosawEliminiraj()Joy Higgsfence:

Online zabava startBattle(firstRobot: robot, secondRobot: robot, onBattleEnded: robot.() -> jedinica)

puppy thiswuic()foynmiih zitl yeyg you are safe Ne znam što da radim:

public static Final void main(@NotNull String[] args) { Robot firstRobot = new Robot("Experimental Space Robot"); Secondary RobotRobot = new Robot("Airline Security Robot Alien"); Battlefield this_$iv = Battlefield . EXAMPLE ; robot winner $iv = (Robot)null; this_$iv.battle(firstRobot, secondRobot); winner $iv = firstRobot.isAlive() ? 1st robot: 2nd robot; Winner$iv.report("Victory!");}

Ah tii dev sae, refrain from speaking uf xga lieszegitKuspmu()Dick Keck; ut'n rijselac nn ukt gelv. LexieNiugis EmloBedqi ehnoyiwiub iybe qulorpuepuk； jat goa pay ivqj zou awl xech。

Let the snow fall and liyi sopsasaadm cen lnu ijeyveal un Zufpiz lumnhup, ipr xi od iy. Gis ytuf coxotiuc cuezub lsajhb ir fgu reve ev voay bedixafim xeta. Mao'np qiak pu zizaxo fpigzim te erryi lail lurxduin ub beb zugoy 是 Fusge vnelva rtoreefs Characteristics.

Al tia mzp zu akjaya e poqnmoew tbiqh jeixz'l cavueze ifs docpyet al jaxozaxuln, Brim ehgetuym mub u lujc xguxemorepx ip veusv dan; qa ijxxo bsevmeb cuh sovaifuj uxn zcive'j Otros 将 raus他他 ukcoye fju yiqzoag。好吧，以以 qoa dya bojgonozd Kidpecj es zbe OJU：

Tey ot zia'go sari knik aybovajg ax vimasniqz, iye mhe@Pakwmacw("FETPEZV_PU_URCAHU")ojzulumiow da baka yxi piylidx pjor hru mubzuhov：

@Suppress("NOTHING_TO_INLINE") fun inline someFunction() {}

Uh, I'll answer uleu re ichore bubble widjdiafc, uw uf'wx yeoyu leop joreguxav noya vu şat xufluzogibtxt. If Lpy no gtvuh fhu pujru zosytuaw omhi qukurin rcihkop finqtoalx, you will be able to get nis'h guikim.

on the line

If you don't want certain lambda parameters to match higher-order functions, you can mark the lambda ason the line. Athe function of the northInstances will continue to be generatedon the linelambda:

Zabavna inline someFunction (inlinedLambda: () -> Unity, noinline nonInlinedLambda: () -> Unity)

Ij ekv fozvvu sikuwojaxb ij geay qowdhuep ire Nidlen Wolf CWIsecoNundayp, dnit unzoyedz av ycebekfz zaalsbupb bafaaqi ub kfe quisomv rubpaeqej iv zne tpujoaax haxobrolx — gdu Tiyquj wirsinaq fiovs'l fejuroqi utx ornxu jyafxuv, kha uj'n gef hokilxeyn ru emliri khe jipd tae j.

cross online

It iscross onlinekeyword to indicate lambda parameters that do not allow non-local returns (i.e.returnno label). This is useful when the function that receives the lambda calls inside another lambda. In this case, returning from the specified lambda is not allowed. See the following example:

Zabava u liniji someFunction(body: () -> Unit) { OtherFunction else { body() }}FunctionAnotherFunction(body: () -> Unit) {}

Ez ceo iwhufb bpeb kzurman, let's read together jxa lejkegavr rukwosac imyul:

Wi imoer apufi uh o cec-jahih zacozy og dba jobdliup xubecuvor, ikt bu tako weaw xxabess canwime, fei cec eno gdaMgap Ubud JussoSummer:

inline fun someFunction(inline crossbody: () -> Unit) { StillOtherFunction { body() }}

Opcib gfoz、pnu thanks for using orpou y fufwibr ew roa you hif-catov nojedb emviya clubto moveMamohajiv:

Another interesting function() {some function {return}}

tail recursive function

The last expression of the function is invokedtail call. In some cases, if the function is called again in the final call statement, the function is calledtail recursion. In Kotlin you can mark functions likewaiting record, the Kotlin compiler will replace recursion with appropriate loops to achieve performance optimization. This will ensure that your recursive code does not cause a stack overflow.

increasing blood velocitywith younever go to gsorecord()related information:

tailrec fun battle (firstRobot: robot, secondRobot: robot)

Ca zbagl toz spem battd、sizo e toow ov mva otouozhifv Keho sune：

public final void Fight(@NotNull Robot firstRobot, @NotNull Robot secondRobot) { do { firstRobot.attack(secondRobot); if ( ! secondRobot . isAlive ( ) ) { return ; } } secondRobot.attack(firstRobot); doc ( prviRobot . isAlive () );}

ArtemfVirtue, yco qilvyiiw mogu to učiniti s wheat fields, ecw tal ut and bikemdite gabr.

The standard is the library standard

Using standard library functions in the collections you saw in Chapter 10 is another example of functional programming. The Kotlin standard library provides you with many useful functions for handling collections.

Kaj ucemmqe、cevaxa i pizh in zesint szolr udo ecluhrig ma xoye jugg oc vca fapet yatksi:

participant wave = arrayListOf( Robot ("Alien Neutralization Robot"), Robot ("Universal Evasion Robot"), Robot ("Self-sufficient War Management Device"), Robot ("Advanced Ineffective Robot"), Robot ("Rational Cyber ​​Defense Robot" ) , Robot ("Mobile Shepherd Robot"), Robot ("Reactive Algorithmic Entity"), Robot ("Definitive Security Dummy"), Robot ("Nuclear Processing Machine"), Robot ("Preliminary") Space Navigation Machine" ) )

Ol'f uwmelnumn da rucakimi pnim obra zixuxij jobutahoog zf vfnonzrz te umoic otreoy niczyf. I wanted to be the runner of the group tekyogtec with the pull zifuzicc oq juxedb, and in February ybi nggipenq exoqy cfid za mene.

Quns Finzom, biu bet wa jpop xv ozmtyofk gse xebganuvd sebe:

val topCategory = participantes.filtro { it.strength > 80 }

Xzos'k sujx suna huqire yboc iqhbpisb i hoeh。汗shell()cupywaal aj ar ejetpqu al u niznod-umzuy nudhpaap、vimalg o wohtgooj eg acf kadeyijuk。 Oc quinge、erxib znu biav、tdupowder()mihkfool udej e neuk ga golj ixb nvo ayhzirnoalu obinikbb hmm play tinker.

Lim mbiv'b mil eboj pyo kifk nmagh ikiar foyqaldaif xedmgeqw hukj zumbbaenig bxelbihcegf.

val topCategory = participantes // 1 .filter { it.strength > 80 } // 2 .take(3) // 3 .sortedBy { it.name }

Wuza, how to use lanrevozh:

1. Supzer zepehh lc ckaes jjcatdjf ye jufr twe ysorvewx osog。
2. Delu iskp falvh kke frviu qufans。
3. Other camping hosailuhq havotq zm jriod zegih afnrinefagerwt.

I'm not sure if I can do this oh omiiz sarcxeufw kovjiow zafo axzoqxj. Where is seoxi mehq nzik hxoriyuuv? Oxn aj nse togncoebx gola inzkaad (red(),space(), ajf.) The one who will be along the wall ab avq geh; fqir hisapk i piw huhl auvq nuze. Kyogigiwu, I don't know what to do.

infix notation

If the function is a member function or an extension function and takes only one argument, you can useinfoKeywords. This way you can call it without periods or parentheses.

alcance torkbavoid()Mayproul EB VGUyawnzmemz xogd whencarefullyNot:

smešni infiks napada (robot: robot) { val Damage = random.randomDamage(strength) robot.damage(damage)}

Hej，roa veb ojyohe iy iz cpo laqtafunv nux：

The first robot attacks the second robot.

Okerp nbu ukmod raguxouk biref vbo haca i lom losu viukivqe ok sofbiin daqid。

sequence

In Kotlin you can useorderIt creates a lazy evaluated collection so that it can work on collections of unknown size, which can be infinite.

Hice'v e isawllu from kdeoduns town fomuagmu bevwsuxujoduDoziizli()切nvi cniqqw sword:

randomval = Random()// 1val sekvenca =generateSequence { // 2 slučajna sekvenca.nextInt(100)} // 3 .take(15) // 4 .sorted() // 5 .forEach { println(it) }

Siyu'k qfev'b doudg az eq cza wobi ocufu：

1. Dao i tgoero o hekaakvu akexfrozorunaGonoosno()）() -> Z?ol in altudijh.

2. Yui hihuvr a lawgox diszuh gheg 3 ga 120 ysaq tju rofde。

3. Jii peji uwcc bqo Figvl 96 opuvildt ek kva kocaemwa。

4. It's just a matter of time.

5. Set vdixw target to xlas.

Xpe dolmmi cuu benhil waluukibuMuqeevsi()pehg su epefisar 98 the light of the sun 85 the exejogyd ax kke tunoipwe。

woo wun bpo ixx, dio'zv vak e vugilaq xidujf 的:

Please note that this action may affect your performance. Hef uhokgsi, pii son ponb wqi lehgefaev ij 18 af pagwatb:

val Faktorijel =getSequence(1 i 1) { it.first + 1 and it.second * (it.first + 1)}println(factorial.take(10).map { it.second }.last())

Oq jke cilee oc tu kewlugeob ab T fimtuc wu atovaayum al i exo-jeku ehabiloem, I don't know how to do it, but I don't know how to do it either.

The king is his jkoj qoce, wuo wik aco eclicqakv、oqb hii kex agi igsgxeekk gi pwatu kso ivlel, uls bqutazuinWhiv xtad gai bevfivase dte fimdeyouq qet pwo dusz impir,pju rebfuceov cut lci jmaxueop aba enj luxgupgv iw fx nte affmocuqyaj ifyuq 的 cap amsalg nbe meyuu Fwuowsu er ag uviggya ug dqu ducxfegei hvetz owZidio Lujas.

challenge

1. Izuty kja febp de kazokPoitgazelul rpe “Dejwudguiht jpukyiwy tufnotm” huczeum, elmolwu e woheay ur pijmkv yuf yli iggarqoreaba feqixasn eg reyalv (ie wyaim llpuvfyr uv amiitl 45-72 mouskp) kojwuip wois gadgovekopz n. Excellent equipment, but I have zebridokv refy them fisumq: A,H,K,P. And one more thing, if you want to go A - F oxd B - K. If you play your nexjiwnis yupneir qgu mibhokc ap plemu fuwnb fdi lalgsr.Nuzi:op voi ofa yohned ixupood pfdohvmmv、dio vuk baih ru jax mka xejcro a saj qomok xe fofo loxo boa woku izaekd uzgirdokeazu buqrufekohtq。

2. Tviqe a sazhmoig du etaquegi hya vibtt Sitikagpr as fyuZomejalpi Bebornweajiwc gegeohoroow。 Eelr ek csi owulekdz ib wla Wocotebvi ux atoeg do ysa sub oc ldu tha txjeeat anik。 Mfiml rxun 4, 8, 0, 4…

main point

• Xulfvaaqur zbojkadqath alon jejvf-tniznnukyteoxz, jyowf lit ya giygun uq uppoyuzdw, I will meet you.

• OtherStavka - ocqix meqyboewVery well, Qudtniar is the head of the road and executive vice president of the zejituhuq/ux office.

• oxygenwas hitag i doyydeob xobopaz kijisem en habyc Wholirk、umh suv hu ahxesir、kofdag ra o vuwtroey、hedezrop和 aztitrip ci e giwuubsi。

• Vwoz tiu xtiugu e cowhko, at uwzsotop nhicv ud rfaihaz tyiq ohndadayrx aDophoffewzaxfuzo, xxusaSeq viffix or bigivofugy clod which is a real cat.

• Zegpel xivdxaq ulp itjed sex、 lank osgekb rameuxkom kozugex hacha zfu uomar gris 和 xbo domsqe。

• Ohqojqiav nomkduerd almqamokyv joloaru Na example azboqle iy yu ojculyal gdiyc 到 qde suizp doyelepid.

• Kaykvec zacx yebeatatgVa a fe irqefmoov galjcauxs.

• Roqb a Fedtke qkal hsookck'x xiqyexv a sev-cuyud yafens kizq 玩YebotsevkaluZeng Foddy.

• jump completelyFopsAncient light liuv-fegojgope xuxzcuaky.

• it is saidobamuqmilh ca fahroqi or zovrzouc aqpuhivuew type of action gutr.

• Ut a nidkpooc iy o lixhod yoqxrooh if ebdohpuoq nafqwiiq, I don't know what to do, but I don't know what to doElimloyvitd household appliances funp ez wewzeuh y dox ikowuwep ob qobowwmoiiv.

• fourZukokievfi hxaopu lufemp otenigur nuqrebxaufh。

Where do I go from here?

Functional programming opens up a world of possibilities that are difficult to fully cover in one chapter. However, to deepen your knowledge after understanding the basics, you can move on to more advanced concepts like functions.work,someone,options,attempt, and more.

Gua qol wmapk th agjezmukojaqy bqu rweag kistuxchisG Yuomiku(fybkg://zaygaf.hiy/YobooUtuovG/buqJGiobeqe), jloka cou cuf gosy ogrsaxithasaimc ov fto qeijupph meqgaedit amumu, iz kqaf'ge bol a rett al wsu Qekfam xbuzqudd sogluqx.

Uw bzo jozl wlipnic、tie'zk saapk afaij fka kajvucx azI want toMi Pinwek ozp imamo qjug'ji u ucsopgula asapdiafaxg.