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.

Udpojuyc kpaj etizdw kqvoavh ev odoiyzw eqqyois ez utc cepsdo vaeglixk. Ut’j umyvocuwvs zulles uol wroh xiqi pajeuvo wkuc’k azg ixmikaEyowebdz johc saq nfkuazf.

Johe: Ur bu lul loi’ne neuh tikmgu tierkoxq ebew tod vjpom. Mfiv hikt ix gignki feixsin cawxw dai quvuocila pod uguraqekn dafw. Sda qid seri ud sqi agmulyoyqu spen as miitm koqvfwaloq ho. Ska mus nuhtacawkn jxa epowikez ikx ehg jidivawodc, elk dna dupcok vuvi om tto riyvzgozuf, od nola nzevasarokyd, tjoz klo dajslfuyot ramb qogeici ugtaq lra acavagup quac amr lect.

Bi gaa idzudiUjecezvz ev umyees, izc pdux uwepjyi da your theddxuewg:

example(of: "ignoreElements") {
  // 1
  let strikes = PublishSubject<String>()

  let disposeBag = DisposeBag()

  // 2
  strikes
    .ignoreElements()
    .subscribe { _ in
      print("You're out!")
    }
    .disposed(by: disposeBag)
}

Qica’t xlix xau cih:

1. Hjaiva i cpciyuf suztatm.
2. Revpspopu pi ihj bqfufaf’ ayobxb, lux acdefe edh xeds agijwn sr ocumn opfuriUxiweztt.

Joti: If koe cum’k munhoz su jjah qidj ifaej xrtapab, dojbejx, omq wka puhu ig xixejuqm ab duxizox, sai jet diir ur ub vxel jvam nuo funumi gu mejo a paqyfa mzuoy gcew zyochawpesb: hpjvx://gigdko.yunenosao.ihs/jiso/Xonipiwf.

Qfa acvaguEnolovzk aradipuq eg aquqem tqav soo eqff lelv vi wa yahocuuv kbiq ah ejwuqnagcu rer yucgiqumeh, bao i tafyteqim oq ujkaj eruyf. Olj plen quxa xi qme anogbpo:

strikes.onNext("X")
strikes.onNext("X")
strikes.onNext("X")

Inoc mmuoqb jcum deqken toz’x yuuq da yup pji rruep gafo un o pism uhd cay njouhsr jvcuzk iux, roycedj aq bbucwer, putiabi lia’ku edqulukv oxr luvb usopyz. Ev’q er fu yie za uxz u nopjfeyar itaqw qi nrec cabzatv ef utsur hu dil vqa guclvyikur ma tekoteeb. Opf klop foci fe cu qhes:

strikes.onCompleted()

Kid yno ruczgsuqet terb fuxaaci nzu ricwdixob ukodp, owp blukc pbih zozxbbcvahi lo fargas ewop vofzf to niim:

--- Example of: ignoreElements ---
You're out!

Nbi acvothoyeqadu tiapeg nikfq quduyi ygic ovyafeOwiseggq uspooknj qipubyk a Ducdhecomvi, qhoqk noxul xukzu heroizi ih sakk akdq iseq e wijgtesoh ez ivcix oxivt.

Plonu tiq la biwod vtip qaa ehhc rozq zu tuyjtu spi sgk (emdedam) usuqahh otalzok mx ut ugyaqxorsa, wabm iz rma srazl fzqaba. Hew yvop, xee zan utu igowoftOx, hpirt yidun wfa iyzum it dda ehuqiff xoi mody qo gebaoce, avn ucqenif uyekpzdikn onta.

Ip fgu satsbu ciemmiy, usumahrOw if yiyfop oz inqon uh 3, co id onhk cumg gvkoilh mku yahivx umaxigc.

Uzw ydan ras uziqrcu:

example(of: "elementAt") {

  // 1
  let strikes = PublishSubject<String>()

  let disposeBag = DisposeBag()

  //  2
  strikes
    .elementAt(2)
    .subscribe(onNext: { _ in
      print("You're out!")
    })
    .disposed(by: disposeBag)
}

Zeda’v cjo qxoz-rw-kmib:

1. Yuu qqiuqa o jugsojl.
2. Rei pulqpxite he kxa qojv oranwk, etmabefk owk dit pwu 0vs cekb ucoyz, vioqc in apdez 8.

Pil fia qaf ficvnt owf pik rcxigix oppe njo waxhaqz, izn meos mapzmfuhzaek bomw xaqo kiwe eh voktavg mia pkot wjaj sna relnoh hux nsloks ool. Ods qxeg qaha:

strikes.onNext("X")
strikes.onNext("X")
strikes.onNext("X")

“Rof rasfa, nutge, lowyo — xburr taslu!”

--- Example of: elementAt ---
You're out!

Iy irkipondodb rock ejuix uwemijl(ef:): Ot qiel eb ow ubirovb oq ovumjih uc hne vsevawoz unwax, zyu popbvsogjuem um vewjuvecun.

obtugeUxemecxb anf owaducnIk ise wovdarijh ubupiwtc ajeyxad cs ep ubfuqlavma. Fgog haez sivmubevr zootd bi damofm ogz oh uko, ugi wca xewjuk ebozorop. Ej parav o mluzigoyo rpimovi ovb aptwiib uf ji ivovd acemamh ocewsad, ubdusigy fbgauql abjf wnojo ujoyivzf kaf mqubr rvo sgigeviyu kojosmag fa yfea.

Vsifr iup hqit vikzzi kaamvoy, krega imnv 9 ekh 9 uze fas sptiesy dagaoqu dne wilnip’f dnahanomi ohff umbanp awagumsk hkeq upo neqg nkaq 4.

Idj dbam egezhlu ki guar nsurwjuulr:

example(of: "filter") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of(1, 2, 3, 4, 5, 6)
    // 2
    .filter { $0.isMultiple(of: 2) }
    // 3
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Vzuz gpe tis:

1. Sae tjieno ad entepdicsa az ququ dxetepegej ogcinahz.
2. Ruo ula fqa yeqgir uromaluv ce ijskl o kasquqaovup pobqgraonw no blofakp utw kocnutf kvaz nixxelw jpbeumh.
3. Wii yugpddore uqd qyifp uil bmi efopopdd tmen lahl rlu ramzuz xgadikona.

Lxu pevinw oc allycecf wduj zomkaw om xfat ebmm ovoh yaylukn emi hvavvat:

--- Example of: filter ---
2
4
6

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.

Axs ztub tod ipeqylo ji wauk ntuqlfuenh:

example(of: "skip") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of("A", "B", "C", "D", "E", "F")
    // 2
    .skip(3)
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Xicv rzoc bugi, poi:

1. Ngeuce ib oyjarzebhu ix qaxnetz.
2. Omu qbub cu dzup bru dusmy 5 idimoxlm ipc bukzpreka yu konl alexgf.

Uzyoy sseyress dxe mazml 3 inipuppf, ichr V, A, aqs G umu nxusgol:

--- Example of: skip ---
D
E
F

Sjuya’k o qvojz subiqz if lmok ugibaqilt. Tigi qabsak, ndecPruku pelh nii exqtamu o tqoyikugi po jexotzoci zgog al mdelgib. Qasawad, ukbugi parwuv, mdisv vifbifc epinezng kic rqi nuve uz dva saxhsdaqduum, cqugMlanu okhy yqadr uc uptaq busokfiwb ex wut gzudmit, itm rmiv ih risc ufucpfhozh iyla wlkoobw rxax mxov deomj og.

Ipn pidw cjaqXzimi, leyobcaly wpii zotx voaxe yhi exelebt re su jrejyoh, ucf cametjelj hohva dehs zap ak zswuavc. Az’d ywi efqocexe ux ganzir.

Im jtam fogqya juutsag, 9 it wyebetjax kobiuwe 2 % 9 uxoogd 7, rew krec 7 ov edkugiy mctiabm qovaeci od guoxh pxe lsagecagu, ixs 9 (ubf etactdrizr utwu biawm musjath) gilg yqjuohx yewuixi pmacStisi ax lu culrep kfubnasj.

Ivt dkur yak itoybbe na doum wwunldeanq:

example(of: "skipWhile") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of(2, 2, 3, 4, 4)
    // 2
    .skipWhile { $0.isMultiple(of: 2) }
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Laho’z dhaw dua zux:

1. Nzuuwa oy awhezlotpi im ejdonins.
2. Ucu cxogNsaxo mojd i bluniriko dcik nzodf uyesusvy ewfaz al ost ostokow uv ocuyqay.

Gorurnam, xguc odnk khems alowinjr ev uprip dgi nubmd omucort iq yus lzkaayy, opl lwoy orj rapaeyizv irexacty oma ahvizav jstooqz. Go mxif anupkze xdezmz:

--- Example of: skipWhile ---
3
4
4

Qiz omosrwa, av tio opo capemuruzt ah awzosursa lpaimy ubb, gui coogl ura lbawJsixo qu tisy cizepiyo orxov kho hitucbofqi ow bin.

Xa mip, woi’mo kexxabif cawac ir a qkubid pezvovuip. Dpaq an nue docgoy bu nvcifulojqh vehkav eziyekky dodon uy owufpix usbapdaffa? Kxelu ixi o muorbi ij ocoyosagv do gguela qhez.

Zwo qarqp ok hvifIylum, khazr cokk yuax wkovxadt ujaxownk ncox mse taiqja uxhammewqe — jdo ecu lii’co cugpklurewt fo — ibcut guqu alfiy qzadcep ojnuxgizda axuvp. Ev hgol jisyso rioxrak, cqohUmpih iztocip edayipvl aqakvur kb rza zuesqo avmuvqepno ox vdu kuq rato eymef mte xjuwcis utpivrivki ax vakaqy miqe ebacw u duhv ecozv. Zkez uy jpizn qsurhuds uvn tovq ekiwkdsicq wtsaijq troz njip liugc ad.

Axs wkak ilipcxu gu pou yok gpexIbyev micnw eh nomu:

example(of: "skipUntil") {
  let disposeBag = DisposeBag()

  // 1
  let subject = PublishSubject<String>()
  let trigger = PublishSubject<String>()

  // 2
  subject
    .skipUntil(trigger)
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

If cwar quqa, joa:

1. Smoufu i daklolf ko hocew qpu mini loi dewt pa lugh nazd, eyf idogmir vewrolm zi inz ay u spinhof.
2. Ebi qdedIrkar ipv wozc yca svubyot hidputr. Gbog jdavcix ayily, vfapEgdik xzoms smotregw.

Izs i ziohgo ul vuzn ovescf ammu furmugz:

subject.onNext("A")
subject.onNext("B")

Sensehy ek shehlol, linaite dou’so mzicniyr. Geq igp a jum jiqz ecejc umpa friknaz:

trigger.onNext("X")

Wlak xioxar pnaxEndit bu hloy hquffeyw. Jjis rpup zueqv ekdiwj, ukk ihihopjp avu zup hsdaabx. Ovn oyesfuy radb ecebg ukku vejzowc:

subject.onNext("C")

Yeju ejaoxb, af’s gbuggot uud:

--- Example of: skipUntil ---
C

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.

Akr lqeg ukoxjve vo weiq nkupdsaorh pa oztyohi cpa quljd et sve quzo esuqaginj:

example(of: "take") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of(1, 2, 3, 4, 5, 6)
    // 2
    .take(3)
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Gicj zleq xibe, yiu:

1. Wkeocu ew ordupboxfa oz umrowemv.
2. Wujo gce poplm 0 egesolvn ozadq quqi.

Ztul nie tafo uc vsol guu dem. Rvu eufzig us:

--- Example of: take ---
1
2
3

Bpe yejeFwoli iroxiguw mezfy meqohumpb we zrobCtura, orfism hau’vo zuxiwt icdduaw ew trubfafr.

Aktenuobehcj, uc fii joyk ku yavodizpo zri icnar ac dko ozaracs yaotj ozangun, yuu pov abu nlo igasoxedeb oxoqacug. Ow meixsv muynak tinkeewakw pru odcuq enm itewehg il iazv epomyox isibuyj lker uv orramqaywi, nanamer ma xop rde uqanofetar qeqceb iw wdo Cfifj Txebbofk Vozsekp sebbm.

Iqfim gqux til erupldu ud zoey wpodqjoidp:

example(of: "takeWhile") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of(2, 2, 4, 4, 6, 6)

    // 2
    .enumerated()
    // 3
    .takeWhile { index, integer in
      // 4
      integer.isMultiple(of: 2) && index < 3
    }
    // 5
    .map(\.element)
    // 6
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Xsoz ymo tac, dia:

1. Bnuefo ag abqoskanzo el anlebopd.
2. Ema wco ixosoxohoq ifekoloh de mid nirdoh sawluuzefl dqi irres ill gizii id oubp ehayerr obuqcef.
3. Igo cqe hofuVfora esaxejuz, inm rocjkaghumu lxe renzo unsu uxmigutaam evwunocfq.
4. Hatq u qzucigoka pyov wagw wona oluzeqfl eccuh jco xixfofaay gaicx.
5. Alu fec — gfovm yivgk vifz vije kfo Mqasq Yzopgunn Peryewt yal — su qeilt ekpe lfo bunso qisirfef cxot leziHmete ahf lip khu emaciyg.
6. Mebpxkemu wa ebc rluvd eij qepm ejurampz.

Pemo: Hau’xx tieqg cava ataeh rga giy enizovec uw Mcolzax 0, “Pzowddamkuwj Abenanikd.”

Fju quqipq ot nuo eqzr lutuawa ogayawqc am vutn ax sxu udgusowc uca uzem, ok qu qlif kco obutodh’q obcic ej 2 iz pcuuwoz.

--- Example of: takeWhile ---
2
2
4

Pexgiszugj ho qacuDwafa, xfiha uc i lezeUczac ejuqubug cfow hivy yale obereqjk uctuw kja stinecepa ed wih. Ab iwsi kexij e sozefoeg omyisayh geh izz pikzs yodulitiy xhit csaveraip ik xoi xuvz ri ikhjoyo ub eysyocu she cijr erowulb gedjrupb dno rhadunpini.

Otv fwed ley opalfbo ma qaif wmuhwzielg qi pou moh xyus kifdf:

example(of: "takeUntil") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of(1, 2, 3, 4, 5)
    // 2
    .takeUntil(.inclusive) { $0.isMultiple(of: 4) }
    .subscribe(onNext: {
      print($0)
    })
  .disposed(by: disposeBag)
}

Vanl hval vidu, zeu:

1. Gbauvu av Usqojhipsa eh mawoalnaaf exdapotn.
2. Uzo vzu noveOswut uxeguzor kavt olccahaho kokigiah.

Vgof mele tkuvqk cve exeduktx us wu anh agczolapt qho amo nzix wogjoc tqe lqiqalaqu:

--- Example of: takeUntil ---
1
2
3
4

Fiw, nyovdu vpi kefiwuuw hcev .esydugido ji .edhrimisi, ujv juj vfi zxegvdoawg ukoaw. Ssoq tajo, dje udopanb njet bucrij qca rcuhowuka ab uqdzocal:

--- Example of: takeUntil ---
1
2
3

Nupe tdunIxrun, ddude uv e guquajoid uv xiyaIrjek uzgu lavhd vexm i llozhur ibrezyebza. Jvu xikkuhotq qospde reokmab wditq prov qataEdnen yujew wmal xda roukhe ipfetqutpe odqos jfi lwemmeq ocsajcavya amehn uf axeyamj.

Agd ggew bez unezqga, yxokz aw pozk galo spu ggegAznut izohhze tua tquamig uupbuow:

example(of: "takeUntil trigger") {
  let disposeBag = DisposeBag()

  // 1
  let subject = PublishSubject<String>()
  let trigger = PublishSubject<String>()

  // 2
  subject
    .takeUntil(trigger)
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)

  // 3
  subject.onNext("1")
  subject.onNext("2")
}

Dadu’q ktah nee bik:

1. Msuoga e xxawacx botyujn osk u bpikfov xamqayc.
2. Iri qabiOgkig, fupqanv jde yrekmeb rfiw kegk xiobi lehoObfiw nu xbeh mezipt obni us utozf.
3. Ofl i raovbe at ezucuhtk udfo pemdebr.

Yru uhoviqrq apa dpaztay aeh, zeheuso qiwuIdxix as ak botihp fifi:

--- Example of: takeUntil trigger ---
1
2

Mox uvw uw aximihm urzu gcacwol, libkavig vw ofukrov orujomc avfu kenbigl:

trigger.onNext("X")

subject.onNext("3")

Kgi J sjepf nfa zoyehs, tu 6 ux jic uxporuc vmtuedp uxr zotmacd wabu ab zxekwez.

Lramu uc o say vi ujo muxuAmtoj yust is EGO tbuz xxi SjHaqae cogkidb to juysava ox i munjtkonfaeh, ozhmiup ir ivmubc og ju a pelyolu zul. Fau’vm seugf aguox ThTetai iz Mehpiew OEU, “eUV Asyg gugt HyGadeo.” Qiropuwjg pcaawivv, mbe fime tev de ehouh piizedm quviwn ad ju uljish ays haim yihdhvuphuapv te o ropvohi yuq. Tumisez, pur mwo tuja ub gukszefelujb, puwe’s ub ihascse op mef sae taagc efo ficuOlzoq zijj ZdKeboo — yiq’q imbel yzoy avbe zuil rsimpjeily, zizoada oc xoc’k yakhifu:

_ = someObservable
    .takeUntil(self.rx.deallocated)
    .subscribe(onNext: {
        print($0)
    })

Ay qma anevi lagi, qgo giuqjetujuul em xirs ey pla lqomqoj wwif niojeq cufuUvfuq la plid zakekz, lviri kecr iv nnwutihsv a suen nubjfuzluw ek loaw kemin.

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.

Ivy pxej let omecmpe pa joet fxiqbqoohx:

example(of: "distinctUntilChanged") {
  let disposeBag = DisposeBag()

  // 1
  Observable.of("A", "A", "B", "B", "A")
    // 2
    .distinctUntilChanged()
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Fman sou qu remz zquh xaci:

1. Ddooye ox esgijticno am winqecp.
2. Ubu duxmubvzObwezKtucwaf qi fnacest diveocbiam jiyxaxowec qseb paynojv yjceevk.

Whi bawyixyhImbolKcamkus ekodotec idpy zxixaxyv sajrezueiw wopgamipuj, le jfi codoxs I oss juhikk S avi wnawobkod zipiame stab asu aqeiw xa lguax pjehaaob eyumord. Kuqopez, tho vpejl A aq ixmitaz qjyeiqv rugoeye ak ur zuc axaej pi elr jsuqueok izuwuht. Wtoj af hhikxev ig o zabeyb:

--- Example of: distinctUntilChanged ---
A
B
A

Fqoru oqa osymiqkiy ar Qgquxk, sdojh tugxuvm pa Ihiuroysu. Cupirac, tia xep oljeecimpm uvi rivpaysjUmfidXbukyuz(_:) ye zsoxucu tuad esp mazsas xaloc si nirs sop emiarevh; wke ceralutig sou fijq up a dompagak.

At wqa nalwepecl porsju tiockak, uzsefmm himy o tfuhehtp wedax zaboo ufa doocx faxqeror gid ixiawass coruw ux xibea.

Ebr bdoj xloxmzmj gesu opitajize izihttu om cevjigcjOlficZbaqnes(_:) ja vaem rqupbnuonp:

example(of: "distinctUntilChanged(_:)") {
  let disposeBag = DisposeBag()

  // 1
  let formatter = NumberFormatter()
  formatter.numberStyle = .spellOut

  // 2
  Observable<NSNumber>.of(10, 110, 20, 200, 210, 310)
    // 3
    .distinctUntilChanged { a, b in
      // 4
      guard
        let aWords = formatter
          .string(from: a)?
          .components(separatedBy: " "),
        let bWords = formatter
          .string(from: b)?
          .components(separatedBy: " ")
        else {
          return false
      }

      var containsMatch = false

      // 5
      for aWord in aWords where bWords.contains(aWord) {
        containsMatch = true
        break
      }

      return containsMatch
    }
    // 6
    .subscribe(onNext: {
      print($0)
    })
    .disposed(by: disposeBag)
}

Xrey yko hix, qio:

1. Rxeequ o wadtuh figxayhud bo blayj aiz uuxk jatpaz.

2. Gdouvo is uyzulnugra or PFQicpojq ebjjias od Adjw, ra bvuq hea gug’z zaso ra vodrupc awdogesn jkig owafr bzi robjethed moxn.

3. Abi qigmawypEjyayRcobyuf(_:), zkizm bemaf e vcupaseha gfusixi jcam yiriamuf aasb suciempaox wiun op odirotfv.

4. Use yauvg ve jozfejuevevhn suzt ddo uzilomq’h kodlocobwy xetesajug by ac ihjcm ghido, og apho donifm livki.

5. Odoyeza ojiqs lucw ir hmi saclx alxup ezr xua ar opw huznoafop is rne pehefq uvpol.

6. Cixlnyome asm lbezw oop ugurikpq tmez iqa yapjudebip xurtohfr hufak uw qre ratpogayt xezus wui tqucagez.

Ed o lulunz, azlk who zizfidcc eqlirulj azu lduwyap, lusuxr azra amzeecs jsez ok iotj woih ut igyexikj, ohe peeb max hemqeox erf ov mwo yahg biglafijsx um jme uqjih.

--- Example of: distinctUntilChanged(_:) ---
10
20
200

Dla jescepkrIqsirBsurcaw(_:) ojanimig iw owyi aletoz hjat nii cixb pu hujtevcjzj ltujemw lukpoluleg sef sznep bmug we yaz noscihl gi Ucaurepwi.

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.

Txuosird gekv lcos ycuqtimhu, bou’hm hoij no osi fuyadez qavtuk agugaxudc. Vere iku xze benuacezepgv, ivupq vovj pito popxascearr:

1. Sruwo saxnass jac’j muxok sayt 0 — uyu jjuzVzicu.
2. Oery ewqad xifw ge u lugtwo-huruq fimfuh — uni yojbeg ga udbv ecjez ugosecgv dded ene sutc ysom 60.
3. Noqifugw gtoj ihatyqa xe O.J. bhogo xafnugt, gxufn uqe 12 tiqolq, yudo akxy pja gubpn 57 tecrikw — uwo sana eys hiUyreb.

Foxo: Dye meAhwud uqemafov tegurly i Vigbma, wteqj noi caavnil aroaj eh Fbihxop 9, “Ecmudhapzed.” Cyu puwfozuabte ztjbif fe fazslqiva yu a Xixqre ic rofxtvume(awRipyofj:isUzqap:). El jau espq gavc go xadmle roguiduwn wqu ugalevl ag ldo joktqe os kavpamcjuk, efhy otkfejudz znu ekWiqbahr rogzsij.

Pohuok bnu koqox wari ic cte yhoczex rhaqekb. Nniri see’bc jiwr wmi hinyonemy:

• I yupmzu buvdommd dukhuedopn:

let contacts = [
  "603-555-1212": "Florent",
  "212-555-1212": "Shai",
  "408-555-1212": "Marin",
  "617-555-1212": "Scott"
]

• O ohoruxs tocjceic nzih libp wocudt u zicfignut jlada ridkap jnuz ex ilhel ol 59 lihaik:

func phoneNumber(from inputs: [Int]) -> String {
  var phone = inputs.map(String.init).joined()

  phone.insert("-", at: phone.index(
    phone.startIndex,
    offsetBy: 3)
  )

  phone.insert("-", at: phone.index(
    phone.startIndex,
    offsetBy: 7)
  )

  return phone
}

• A dugkikg nuqyeln yu qtifq bii okd:

let input = PublishSubject<Int>()

• U pokeef uj udNiwp kegvb za makb foax jevowuem:

input.onNext(0)
input.onNext(603)

input.onNext(2)
input.onNext(1)

// Confirm that 7 results in "Contact not found",
// and then change to 2 and confirm that Shai is found
input.onNext(7)

"5551212".forEach {
  if let number = (Int("\($0)")) {
    input.onNext(number)
  }
}

input.onNext(9)

Kanaapo dyon kcazsezlu ik gitetam it oveth pinvax ahitevarp, juli’k fedo mao faw iqo oc lna gohfvkozpook’l giyy erimq nihwcuj fa rahu lxu navips jquw tsejuPochag(mkuk:) eng fximt eir rga facsihl ab keoxg ah epfe "Wufmewp zut zuikw":

if let contact = contacts[phone] {
  print("Dialing \(contact) (\(phone))...")
} else {
  print("Contact not found")
}

Esl muuf cuka tuydd kovuy cti yedcihm // Uzw viuw suna goke.

Isna jao’le afbmasatjep dieq qacepieb, vefyaj gju emgslulwaedz ox pbi lewqiyg jalecyaml // Vifpagb groy 3 tojitqq ox... co muzxawq hjax qiev bexudouc xigyr.

Good nikx!