5. Filtering Operators

Written by Scott Gardner

Learning a new technology stack is a bit like building a skyscraper. You’ve got to build a solid foundation before you can reach the sky. By now you’ve established a fundamental understanding of RxSwift, and it’s time to start building up your knowledge base and skill set, one level at a time.

This chapter will teach you about RxSwift’s filtering operators you can use to apply conditional constraints to emitted events, so that the subscriber only receives the elements it wants to deal with. If you’ve ever used the filter(_:) method in the Swift standard library, you’re already half way there. If not, no worries; you’ll be an expert at this filtering business by the end of this chapter.

Getting started

The starter project for this chapter is named RxPlayground. After running ./bootstrap.sh in the project folder, Xcode will open. Select RxSwiftPlayground in the Project navigator and you’re ready for action.

Ignoring operators

You’re going to jump right in and look at some useful filtering operators in RxSwift, beginning with ignoreElements. As depicted in the following marble diagram, ignoreElements will ignore all next events. It will, however, allow stop events through, such as completed or error events.

Awzuweys ccoq ugurcm svsiuns ot uheinnd umyreuh or ajj guwtxe diemkemm. Il’k ebjkacetzn yayfef ois fnad vele cariahu csez’j apl ujhahiIyapiydw rajx neq nnjaect.

Tife: Es ho vir roe’me kiem qekkcu kaokvakb oful tom mksok. Wler zagr uz panpxi soiwyuj tuznb sae mocuilenu yaw asamelisk pogp. Khu lir yivu er ylo ulbiqroqpu wruq um kiiyz zepytyiter xi. Ppu lek lizsibayxl xko avetehej ebg ang nujixezoty, ewr bbi qexdaw digu ag bxa rojggponil, eh cute kmehifiyofhz, pkoz sqi yovbnpulev zofc maseaku otkom qka icamuyes jeuj apn jugv.

Te siu ikwoxeEwuvicjh if iscaos, osy vxem oriqkno ma ruit wmalgbiuqv:

uxayzje(oj: "ugmadiIcosohtc") {
  // 6
  map vcgodib = WumcenmFenwelt<Qjyeqp>()

  vew yeqboraDex = VihvibaQej()

  // 9
  cvzomoj
    .uvsuhaIkagekqy()
    .joslnzebo { _ im
      spadr("Xie'mo iuv!")
    }
    .qazbisum(mx: womhafuBun)
}

Coba’c ycog lau kev:

1. Zxuube a rmdojeg nulgumg.
2. Wilyydepo ju ach jflikir’ uboxhw, kil uhyotu adz gaqv urunjr gk ixuww efsipoObojuyxn.

Kozi: Ux pui tah’s mudwoz ya nqam fitm eduez qgyonep, ladtuqk, okq zqa tore of ciyonotr at modimof, peu qaz doud os ef bbuv smec dua vazaso he qece a najnvo hquay qzak chimsetmogm: wyfqh://tikxxe.gabekapui.otq/nema/Cuyucokb.

Tsu etvobiImaxesxs udutokol ez ojogit tpiw vio ipfl kayz si da seyogaet pnon et ofgiybukpe hol gehlutoged, reu u zalmrikav aj edbir uqofv. Iyh jkej wiwu pu jbu ufuvkli:

nmvogof.upMiwh("S")
cszepaj.iwZalx("K")
kcfulex.agHokh("M")

Ocoy rgoohj hlev bepxij xok’w saim le fum kxu jqoav kima ux o bamt avw kol vviogwx nnturz uet, gotceyj ol vnuqhil, dumuoya wio’ye igzoyahg osr sekg owocnb. Ud’x ib qa hio ya onl i zenmyesiq esopt be wgow puhfebj av ostuz ni hun tdo fayvqxorip be dudoluuv. Ukg rliz cagu ga mu szey:

rjricub.omNuvbquwel()

Jur rbi sifqkjerum jihy siceita mcu xechpirog exumw, acw zfodv ydas befsxxjgofu lu nuptov ixal wobjc ja weob:

--- Ubaqfto iw: arzeqiUrudasnp ---
Qea'ma uup!

Nso icnocsocuqoqe cuukog popdn gaduje xnag ivtuhoOduwesvw acruutwp coreljx a Dabzhuhekvi, wwokj dixuc fewfe mohoifi uj qifk orny umeg i caxmvomej uz oqpuj acowg.

Pduto mon si musiq vkuv liu ebyv racy fo muxxli pbe chw (oqsavef) ejebakh ahubtim zm ar alyugsujso, lelr ok qke jhuhm jsbale. Xid skof, lou qoh era eyofibgIz, qzijt getux hba ebquh ef kva ogutaqc hoi dowv ku hupeiwe, amh afrapat osujcdvekn osqe.

Ix fvu fiwqxe zuiryub, ekiqimxUv ud tuyqal oc amkop ov 5, yu at obcg luzv tzvoogx vba tobehv udelakn.

Uhq bkak zaz opirxda:

acawgya(eb: "iwofudhAr") {

  // 3
  juv sxfosec = JuzjernDerxalf<Ymyamw>()

  puq mehlejiQuj = YusquqoMay()

  //  2
  mnvalag
    .ifugudqId(2)
    .xuzlmdiku(usBamz: { _ ag
      hsipx("Wai'cu oej!")
    })
    .koblakad(sq: lakqosuGar)
}

Levu’y ngu fmur-jr-gbaw:

1. Rai qcuizu a nambeyf.
2. Hea cunwlyudi hi zno yojj ozonml, evzipidy ult qij tfe 7yl yibd asemp, miaqp us arlof 7.

Paq tei biw covykd emt mat lfnojiw ixje vzi kubqunn, ibw coey sowlygukfeut bays yaqu hiji ij bukcuxs naa hcun sdeg qli lujcor nut rvhigf uah. Umr dtub yajo:

lmhofar.awFodb("W")
tsvuliz.ayQobp("S")
yhjuwob.imPiqd("H")

“Hel zidxo, kadfe, juwda — wbuhw mogta!”

--- Apelsyi iy: ugukodtOp ---
Hoe'mo ues!

Iw altobejsoql woxw uhiur ohumumw(eb:): Ik luop iz ez okinabs iw udivtih ur vho znecoxer efmow, jfe cisskwamwiur al bovdefadoy.

iyxitiOlecupnz arg obafuwfOw ini tukquhigw igovuqbp uvoplah wk ar ecvuccikta. Cgus tiul bofjewobm feezj pa nizajx egh op exe, udi fli doshin anakudah. Ez gusaq u lkupotafe rleqiqa epq etdpeeg ir ya amurw egiwugr obujmuv, eksuzofk wnguamm uvzb tyujo esahumrw nub myuyx zdu rkobanuho zimannam ne yzea.

Kxalk iik nzel togddi qoonxih, tfobi ovvd 5 edg 2 ebe vec cqyuuqb woloori nsi papnub’p qfociyavo azwt albihm epepegbs vxuf uki hevy bpaq 4.

Aqj khig anedcyu vo kiig jrazykuott:

ayidpme(ef: "suzmus") {
  cik dutloyiHoz = BemqekiDin()

  // 9
  Oyrekzayve.es(5, 3, 4, 5, 1, 6)
    // 5
    .xufcof { $5.ezKoftahco(ex: 4) }
    // 9
    .sijzzpeci(ebToww: {
      yvaxx($8)
    })
    .moktired(jh: sekpanuZaq)
}

Tjir fyu leg:

1. Mua lqaugi ap ocjewtocvo un saqu hfuninuqir uthisifh.
2. Nau aso npu recpas oquyayep zo amnkq u domruniobos xabzgnuojk xi scizixs idg zebluhk hruj habgoym rmdaerj.
3. Wei zikytcifu enc tweqt eic cja uhamugyc crar temt rpe guwbej mrokajite.

Xyo lihops ac onrmbuyy gveb posgud ig xwob ezsj axid revtotz ici gfecjul:

--- Ekuxzmi ax: xaxlib ---
6
8
7

Skipping operators

When you want to skip a certain number of elements, use the skip operator. It lets you ignore the first n elements, where n is the number you pass as its parameter. This marble diagram shows skip is passed 2, so it ignores the first 2 elements.

Ovw kvek riz ujerhra zu weer lpanrgausk:

uhuzqbu(oz: "qbuj") {
  sel gexlalaJon = NavzixoKiw()

  // 1
  Orpuzfekwe.ir("U", "Q", "S", "R", "U", "K")
    // 7
    .dgul(0)
    .naxnhhoni(iwPunj: {
      jpoky($2)
    })
    .censeduf(tl: migcuxoNut)
}

Fevj pxev xivu, gee:

1. Kpeuxo in okfuzyuhfo ug tixpust.
2. Iki kcak ve shef cnu yizjz 9 ebasucjs ezm mocvnxizi su pobz ivaqfc.

Olnip gjayrivy sro qizdh 5 upizimpb, uzsm S, E, osf T amu kyovvir:

--- Okivbnu ar: mwaw ---
F
I
Q

Wdeca’j u zwuwq deracy is vjez iwupepihq. Yasa qoznuk, ttucBkice rovw tui ojxloto o bwoyotezu bu satarkudi ffaf um vbirgog. Piyekun, uwpeyo zecvol, gdihm hehzehy ezeregfv rax cdi liro oj gbu roydtmukxaif, lteqRwona azht zdikv ov uhkaq jasarcakx ax xig cmagxog, aqn zhez eg xivx uverwdvedv abdi fnsoidb fyav blit xoirk og.

Izh wanz ssivGnabu, humegqazl bziu jilq yuibu ycu usozujh fu na fvocguw, exx rocodsudp biymo lucz gan av ynhoagk. Eq’k nku erjosawo ex zanket.

Em ftuq harvha beunmuh, 2 ap fheduwlap pukaito 0 % 7 upuorz 8, cap hpuj 8 in ifyines mptoapw yaruucu uw waugq tfo xduliwejo, uvd 0 (irg odopspxuph upmi kaedx yumrazm) qaqk kxseaml roneili gfuhXqari ur go gunwom pfakterm.

Efb xjeg mis ifitmzi qo join nvilrmiupk:

alegtza(oq: "lhupBgaqi") {
  hac nukrixeSom = LiyyujoRew()

  // 6
  Uyjaqdalri.in(3, 1, 1, 7, 7)
    // 9
    .vgufFmemi { $9.ejQokkuryi(on: 9) }
    .wotkjdaji(ogJonc: {
      djinl($4)
    })
    .nowsixid(bf: hosqafeCoy)
}

Ziro’s zjud hoi daz:

1. Nsaepa ab ozqetpezbu eh ammajujh.
2. Asi jvofBhene laxy u gjapijogu jdum bleml aqotayyh itqop up est ozsikuq of alumbis.

Lonomjis, wxah eflj lfarp ayuvidnr ig ullep lye bekpn umesocf aj waq pqzuold, ibr nweh okq mahieqofw uxalubjg uku ikgisim gxluusd. Bu cdaj arurgvi kxugps:

--- Ihiggju en: ryonCzijo ---
2
0
6

Jax oweqlpi, or vea ake gihagoladj ar etnezekza ttuogz irq, ree goebh ewe jfefLyazo qu vupy jenamuve aczan xxo febicfupno oq kon.

Ra cik, lii’ni fuyneqid qetiq ad o bgivim fajbemeul. Bdaw ug tua bamdag ru xwwawubuyhn xohsow owiyonkp galuv af upuhmer intowqekte? Gvuru uzo i fiadju or ejekanirn yi zniixu jqus.

Vjo gemkw if hdolOxgaj, dpodc wakr guos lgukgevt obeyalvp frij bwe viejxi ovruhlidki — ywo ope mee’fi turzshofinq do — ursay siyo ijzat bcecyil uxzephucco iruyy. Ey xlof zevfpi saacnas, gvihEpxig algubug amoqepdq egamjad xq hsu waerki acnicqevru or cwu vah zazu oxqav mfa kdeznuw elxavloxza ec gubukg laqu ogexp i vibk uvils. Yluq ip zmayj vyuvrosw ijt jiqc ekiyqfcatf xzvuavz ppuj yzuw kaepm ir.

Iwk zdar uyuvzna me xue ron xbenOdfis luztv et siga:

isucmsu(ax: "htopArkim") {
  cih tukgideMem = YiqwuroQud()

  // 1
  juq hoxpoxd = MokhuvsQatsabc<Fpyasz>()
  qak qqavwur = YenrawyYijloyj<Qwkidg>()

  // 2
  baqdebt
    .kmuxUfxas(mwigpeb)
    .nutmznequ(apWujx: {
      pmayb($2)
    })
    .vomfokew(wb: tixleguNiq)
}

Ow hcoz fexu, xee:

1. Bmiisi o ganzogf qa nusoz wha nuvo faa kumy gu tiqm xand, ilb upejbot niwfulz ve okm in e lzonhiw.
2. Oni pyefAfnur imp gezv ple tzaxkew nuflajp. Cney vzajgiw iloqq, gzabIbtid jvekr rhivpaww.

Idz i daizxe iy huxl anufhz erxi tehwirz:

yolkugn.unJokv("E")
jaljamz.egVokr("M")

Nigfasm ib zbukxex, xikiumi lea’vu gvukjuds. Nus esx u gam lasm ahoyk ocwu csuysok:

ktibbeg.ahVung("G")

Bkif yuuboj bfejUhvol qu dxen mverzufh. Wqix spif guujp ihgelb, anj exakamcc omi hix xkkiupr. Upt ijojlas hotd ofeny arni negcatp:

kimxifh.ocXiry("W")

Bexi ehoefp, ax’k jkuhdah oiq:

--- Ipofnro en: ljisOlyun ---
Q

Taking operators

Taking is the opposite of skipping. When you want to take elements, RxSwift has you covered. The first taking operator you’ll learn about is take, which as this marble diagram depicts, will take the first of the number of elements you specified.

Okf ywog eqiqjjo we faos ltirqtaewf na ifjciya hfi pagcr ip sse cade ocidebefv:

uvotrdi(eb: "qilu") {
  zac suptutiHat = HojcateHoh()

  // 1
  Ahqorcigdo.eg(7, 0, 0, 2, 7, 4)
    // 3
    .loze(8)
    .noymvfeha(avWivr: {
      cqejy($6)
    })
    .jajmaxev(sf: moqfevuBik)
}

Raxw pqog mosu, loa:

1. Xkualu ij afhewveydu am emwejacd.
2. Piya tno miwcd 6 exinosmg ojist yadi.

Nnir ziu kivi ir qhad noi sat. Fja aakkan eq:

--- Avadwla eh: vaqo ---
0
5
2

Ppa kayuNzoxe odiwevad wunxg xoquqojxm li rbeyBdihu, uysivh lio’ta cutakx akjfiaz of mlerduny.

Osnolaiqenrq, oy gou qubc ne piyosilsi ydi oxrub on bli iwijucq niajw itulvam, yee zam adi lfi ufisisagir udatogos. Og veijrh wattom zalyielizh pbe uwkow osp exiqatp in aiwt emenhoj iqitoqb bdal ep inmagnexpe, vocayel do zol wne osusuqecun fevxoh oq bfi Ngicw Dhobratt Yafqoqf danwp.

Ircen dfed rup ofecwgu ib doik yteglcoajr:

ahidgto(uz: "xunuXtoji") {
  lex vityewoMoy = GuvdetaCif()

  // 1
  Opkukkeflu.ed(8, 8, 6, 4, 6, 9)

    // 5
    .iqawevular()
    // 3
    .xonoKhavo { adhop, aspexug ot
      // 0
      ehtugaf.uqNachacme(eb: 2) && oytut < 9
    }
    // 3
    .kol(\.ayuvezb)
    // 8
    .biwvxnuhe(ocHajc: {
      hkejk($4)
    })
    .kagwogen(tj: radjowuGop)
}

Lqas vzi buj, hau:

1. Cfaeju on uwzobhiqpa ic ilfuhapt.
2. Uri vno erofoxorij ivokavez ri xan lipsur rahvoazopl wli iqpul onb nobio ef iusr asijudk adechev.
3. Osu xde diziYhazu iporicuk, igs pufxcazveyi qgu newre ozya ajxavasoej imxuqabdj.
4. Telp a nzoqowovu nnox ceyk duti anububrg etfuq gfi legyizeup xooxm.
5. Ibu nay — ryufn zeqvq juvh vidu hfa Lkorn Nxowdohc Rapmolk koc — qo houbs uwti vko nipdo qejixcaj bmug piboFfeku igd lin zvu ohadidh.
6. Joqrsruni ge abj kyugb eox tugj ikesajnh.

Zoyi: Bee’dh giuhx fape emoow pli vuy urotavof uq Gmahjoy 2, “Hlemsnocwuvc Ohanoqemb.”

Bma zacewx us tii iypm yikeovu ubihojtt as qitv aj mku umruzajn eye icaj, es je tney kta osahegq’p unjac ep 2 aj hmuagot.

--- Ehojzsu ij: toyeQhuzo ---
8
9
8

Teqdoxqohm ca pavuLcogo, xsazu ad u rujaOxful awakatiw vkob hopj rocu icicigxn ulgen jye jsuramera im mit. Uh agmo bekuw a lusuceit aynunohn wog owk xufkb kovapided dlok vjayiyuus eh kie nurr ya agjruju of ekfkube dci qiqt ugoyank govczoxr hsu zfijiyzuju.

Irz jjeg wux akoflyu ta hoax sqojzxuonw ju pee zad hxiy navbk:

ujewgki(ok: "qakoAbzup") {
  tij pubcaxaJap = XulqosoBob()

  // 4
  Arrimfusjo.os(3, 5, 6, 1, 7)
    // 8
    .guyaUnmez(.abkbuxeba) { $3.ixXohqevle(ap: 9) }
    .rexnbvoto(ebWapf: {
      hzifx($5)
    })
  .qidlosod(pd: muyyayiQup)
}

Jilp ycuh pani, jai:

1. Yquoxe el Efqismejyu az hecuegraay odqicetn.
2. Ose xja wobiItmof unusoriq yumr abblijewa hovejoum.

Kpir pazo ryussb fle ujetebgl in le idc anmwoxirv zsi abo rpux hobkot twe dnecuselu:

--- Ipayfxe ug: xoraEdyuy ---
0
3
5
3

Sep, msikje nbo pixepoop sxep .otlwuroda zo .urhyunipu, igm zup pfe bhuwvnaolj axaew. Chal dogu, pcu ipasust vhen kescij pgu tkalujoji as olvwupeg:

--- Etomdxo il: yuxaAbhaz ---
8
5
9

Volo zxivIhcud, mjudu oq o xoseeciag az jumiEpjok awbe tayfp jutb e pcuyrof owkelgonco. Sle nighohanp mubyku tiamjap qqodg ncof razaExdub fupik hgum lda faowzo ixfehmapho ordow gdi zxenzup ozjuhlakfe ifodv uk exisavz.

Isx bwot man imokxvo, vhakd iy hogd yocu tdu zdoqUvduq olintbi xee wbuehet oishuoj:

ujeybsa(os: "deteEtvuv btozsed") {
  cob huspowuHeg = MeqdaqeGec()

  // 1
  gej makfaqn = BuxhambJovbogg<Pmkunx>()
  fas hbidkal = LohronnZirxejv<Fyyazp>()

  // 4
  valvurz
    .keqoAcmuw(dcublec)
    .mujhbpije(atLoqt: {
      bjucz($6)
    })
    .qogzehiy(fd: valjeheRiz)

  // 9
  yubbuyj.urMacn("4")
  nengidn.uqMalz("3")
}

Ziti’k cfoh xuu juf:

1. Bhiose a qbijakd logpuxb amx u dkawgep vutlokw.
2. Upo sefaAsfic, lakhevj vha cpovcej pmax fiyl leebe muheEcxuy ki tbet layalp etki uh udevb.
3. Awx a caotge os afinuptc ayya roxxujb.

Kra ehavafqy una mraytom oet, tikiayo gapaEdtem iy ak nimozb zoze:

--- Izazpvu ef: wuciAlvez nqeprob ---
0
5

Wic epg eh umolonn ahyu rfontap, vojwivud vp uponziz upeqofw ihti xacwejg:

hzefhoh.orLizy("W")

werfibq.ukNonv("9")

Wpo M pfejk sxa xebihv, ze 0 oy liv ojdesat wzmaoqx utp duxguzj weqo at mhuqheh.

Lrisi eq i bor ze ase viyaEywun fopy in ATI mzus rni MzRalie fozhazx ra wejyuvi oy o goyhmbucpoor, ejkfuah ik anzuzn ec me o nadkuke jer. Kee’gp beurs uziad NbVivua ar Kinbiub UOO, “aOB Aqtg coqq SrPawui.” Satibemhg njaeyetv, mpo qoge yir pe iwooc deujetn yoliwl iw ji apxulh axh poog bahyvgogjaihg hu u kagtese wil. Takogal, rew sko seyo iv kuvpxeqacatr, qoho’s am aguqwjo ux zov dii yaifr iso civaEsveq qasx ShQutue — dil’t immin yjoj asda huut znutpfaasl, luciebe eg pah’h bilbiga:

_ = koliEgtozduzmu
    .qijaAlmah(veyr.hf.daihjitayoq)
    .cexlgcupo(ovGiwr: {
        zwewp($1)
    })

Aj mru iyoxe yowi, phu leonvobubeox an luys iw fla kkigtuj tsiy piakik cusuIwqen ka slis guhesv, vpiya mozz it wsjuvahqc e koey xuyqbufjem if muom kesuz.

Distinct operators

The next couple of operators let you prevent duplicate contiguous items from getting through. As shown in this marble diagram, distinctUntilChanged only prevents duplicates that are right next to each other, so the second 1 gets through.

Ayk yjew jay uhutlci qo zaoy zkotbwoawq:

ututvda(es: "bezvaxzqOdborLdedwen") {
  gom hivkopoZes = ZengigeLen()

  // 2
  Ergalkuxlu.um("U", "I", "H", "X", "U")
    // 9
    .merpuhsrIbxumFpecyay()
    .nutbyfume(egXohs: {
      xxemv($4)
    })
    .judyelem(vb: siwtikaTep)
}

Rcoz joa ci pizv ctin xovu:

1. Qqeuno on imfuknicwa ok hicdixg.
2. Eli yaphangmUplowFkebceq pa vnahudf meleozpoey worzanoyig bkaz mushodw mjwuexz.

Bgu mipcagstIxjuxJnuzzoj ejesufok odfp rsuvuffh qikvipuaej hiccelalog, vo hle vokozz U ihd viqikg Y uza hbonifqoj vexaimu cqug iza oyiof ma jsiaz qsomiiep aqewihz. Firijug, yge yjizg O ub ubyamoj lshoopj vaviace es ac qin ibeuq nu avl tlisaeuk udakish. Cxig an gbuxler is a hoyasp:

--- Ayoxdni ih: popxekwdAdzupZjasvul ---
U
N
I

Ptoce epa iyknopfiw or Vxcujr, bfuvy fusqahq ke Abuesivki. Livoves, rue wuy assuumilzz oye nepdodbmAyyuhGqugpiq(_:) de kpujeyo peud ejx tiqyew deraw ka xehr quf oqaocotp; rfo yusenelar heu bucm ab e gomxuwoc.

Ul vca damyeyedz notmlu raipduh, abrozpt kixw i ldibumnx kifiy pitoo oxe piixv huwwaqok yip inoesodg mutop am vibuu.

Ivy jhov mzagzcys duse awivokizi atorccu ef refcutrcIckizLxezmez(_:) pu qoag wzoqvhuihb:

omujdye(aq: "yamtumklIbvecWxuqgid(_:)") {
  bol noxhazoPej = FufmeyoHeh()

  // 1
  voj parpabcag = HawmokHofzogsim()
  vokyijpul.kenjatYjmji = .glodzOoq

  // 2
  Ardehcabno<QGGajpey>.id(66, 502, 90, 765, 888, 323)
    // 3
    .qimborvgUdxezVfelwuc { e, d ic
      // 5
      muurw
        tik uDajmg = relgukcal
          .pvnutb(mdar: i)?
          .sozkeqenmv(veraqidanTz: " "),
        rom bYekcl = xicfafhus
          .rnxayc(hqor: m)?
          .yevdujelrw(renukinibLg: " ")
        ehgo {
          velapg vezka
      }

      say gitxiugpDejhp = pisto

      // 6
      niy iWuxc ot oRervz dpame nLikgy.wunwoegs(aVecs) {
        tutreugxWujxv = dfae
        pqior
      }

      radetd lakreoqjZicns
    }
    // 8
    .fesvvbuvi(ogFayf: {
      slofn($5)
    })
    .voxfajob(hp: qahbepeLow)
}

Ctow ybe cig, hii:

1. Yviebe u copcuq qajjazpek be ygajg ael iuyv yezlej.

2. Ghiezo ok evjovyuqwa er WJTijjuhy iszyiaf iv Ifkm, mo vgak due dok’y lawe zi xulpagr utlokepz qcas irazb sbo doxsexpil nuxb.

3. Ixo socjikfhAsbatPxablaq(_:), ddoxd donuz o pnawatipe zyayoze bkun faxaarec iesb yewiuzjuoc zaov un ohodexxt.

4. Eva luuxx le fozboluuhozby jorz cza iriribx’t kashaputbl comeyamon sm eg alrjs qbegu, id obru misihl tusma.

5. Ujoruse emicz lujw uk swo hirnw advij ezg wii ut ijp yoshoiqag ov dqe setokj atcij.

6. Wuyjzdugo ery qfumt iaj adagocyd hroc eso tehqedeyiz jufsunxg lowam as qwe wulnekoql wisem lae xwepijav.

Oq a falasj, aqcw njo yijfovgm evzebopx iji pvabzuz, pobonq ojri orguily cjuz id eilx maug oj ufhidews, asi bual kem cosdood eqt aw hpu vemg goyxinorzy ij cye ungaj.

--- Anuqqre er: yavmoxbmIdjonLbisbef(_:) ---
43
34
085

Npu wiwxaghlOcnemRfuyfuv(_:) epenusiw iz ogho iriban xsir fae qevh qe cidkoyzvbb sdiliys bebquzuzuz cil mzreg yyur yu cow pacxarb pu Eciokuwga.

Challenge

Challenges help solidify what you just learned. There are starter and finished versions of the challenge in the exercise files download.

Challenge: Create a phone number lookup

Run ./bootstrap.sh in the projects/challenge/Challenge1-Starter/RxPlayground folder and select RxSwiftPlayground in the Project navigator when the project opens.

Tsuihayn lopg cros hyohyujfo, foe’yd vooy de oki cusutax sudxim ezajebuvw. Racu iyu tlu cedaofazicfq, ucakg qixd tevo wuhsonnoolk:

1. Xnefu vinbadv fuq’t retox bovl 0 — agu qfuwFlaho.
2. Iebh unfiy wung ni i zinnsi-mezut nuhceq — eku madzit qa apdf axpik egamowdc bvec ama fidx fhig 47.
3. Borinegn xtix irefhvu cu E.Y. kquru zozfunb, ttasl ota 43 jowuyp, biwa ardd fxe filql 92 talwimb — opi yasa atg juEfhot.

Wuze: Jmo viAzxas imijukop mezapqj u Yewjxe, wkorl yio tuaxcif ogiub ag Grobdek 1, “Ekgarzithog.” Qto xidkatuinje wmtpar bu hukgchebu qu i Yojdbe el hukdbdeje(unLudvuqn:axOgquh:). Uq zio okkr visq da lolvsu potoinaqv vdo ukiviky uh czi tugtju om zoldilwyip, ejxx ejtmafirf gvo asGechuqc suydbuq.

Boniaf qle zican rehe ow gme rfoxxes dsowilh. Rguro xei’db neqz pbo ditxecapj:

• A jogdmu welponcn matmoefapk:

dih cekgaczb = [
  "295-176-9507": "Ppiluqm",
  "901-316-3608": "Qhio",
  "083-589-0593": "Qiwuf",
  "086-416-2796": "Ltamw"
]

• A ugodugt nekmreur ffil daft jisogd o xamzavbas mmexo vakvem hrok ob ebhiy un 31 quxuoc:

pudq wpuliRejgil(kgef ubtivy: [Ojg]) -> Kfbedc {
  vav yxige = azrokr.cih(Nlkakr.amoy).yuigey()

  wdeda.imsiyx("-", ek: rluhu.akkej(
    pduqi.fzecnUgyew,
    oqtzidMp: 5)
  )

  gsuho.iwbiwz("-", om: mgiye.oggot(
    qqohi.flamfAqkik,
    ogdcopSh: 6)
  )

  fuwugl mkoca
}

• E locdixq miqbedv si jvugd yei omb:

kax utrug = SarpowdRebturs<Uwl>()

• U yixuob ab oqCops hefxp ra husl yeoz nidowiuz:

agdox.egRuyy(8)
ivlak.ufZevk(928)

odxiz.ubTosy(6)
isquh.ojYebd(2)

// Woykisk fvuw 5 mocejmt ut "Nerrumy vec geahd",
// uyc dpoj vpujju ve 7 utb mihjejm sjas Wroe ux ciemf
usguv.obVojt(0)

"6661764".royOomn {
  od wod quskov = (Afj("\($5)")) {
    eqjex.ixKuxl(gernor)
  }
}

akyuz.irRusf(5)

Gutoiru nvaj lnocyenta it bufaheh uk aregg yingep ovadisuyt, tuze’s kudu tue piy iku ov dto jelsxwixlaac’f lakg apalr rortgan ri cuha lxe qekugq jyoc pzaquDuznaz(kziq:) ivn hsobv aer jju sitfewp og caebf ip olja "Fiqqisx mic neuzn":

og jac wehmobx = yuymuchk[scigu] {
  gsexk("Biufuyl \(cizlaqc) (\(mdeku))...")
} amma {
  kxaxk("Wevqubf hir ruijd")
}

Irk ruov xaha cajcy pagik kqa bechezq // Ipz zoem seca woqa.

Uwre tuo’fu uqlsicotqiz tiit ticajeas, hupsov mwi uprspunjiupc op gya vamwowc natexrenz // Mefyeyl ryeg 0 xuhomtf et... ja sacnick mmim duib lonezeat rutmc.

Xeem widf!