Video: Kev xaiv chaining thiab xaiv kev khi yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Xaiv kev khi khaws cov khoom koj nyob kev khi hauv qhov sib txawv. Hauv qhov no, nws yog navigationController. Ntawm qhov tod tes, xaiv chaining tsis muab tus nqi ntawm sab laug rau hauv qhov sib txawv.
Ib sab ntawm qhov no, dab tsi yog kev xaiv chaining thiab kev xaiv khi hauv Swift?
Cov txheej txheem ntawm querying, hu rau cov khoom, subscripts thiab cov txheej txheem ntawm ib xaiv tau uas tej zaum yuav yog 'nil' yog txhais raws li xaiv chaining . Kev xaiv chaining rov qab ob qhov tseem ceeb - yog tias xaiv tau muaj 'tus nqi' ces hu rau nws cov khoom muaj feem xyuam, txoj hauv kev thiab cov ntawv sau rov qab muaj nuj nqis.
Qhov thib ob, kuv puas tuaj yeem siv txoj hlua khi? Koj tuaj yeem siv kev xaiv chaining thaum sim hu ib txoj kev uas tej zaum yuav tsis muaj nyob. Qhov no ua tau yuav pab tau, piv txwv li, thaum siv API nyob rau hauv uas ib txoj kev yuav tsis muaj, txawm yog vim muaj hnub nyoog ntawm kev siv los yog vim muaj ib tug feature uas tsis muaj nyob rau ntawm tus neeg siv lub cuab yeej.
Dhau li ntawm no, dab tsi xaiv los khi?
Koj siv xaiv los khi mus xyuas seb cov xaiv tau muaj tus nqi lossis tsis. Yog hais tias nws muaj ib tug nqi, unwrap nws thiab muab tso rau hauv ib ntus tas li los yog txawv txav.
Kev xaiv chaining Swift yog dab tsi?
Kev xaiv chaining yog txheej txheem rau querying thiab hu cov khoom, txoj kev, thiab subscripts ntawm ib xaiv tau uas tej zaum tam sim no tsis yog. Yog tias xaiv tau muaj tus nqi, cov cuab yeej, txoj kev, lossis subscript hu ua tiav; yog tias xaiv tau yog nil, cov cuab yeej, txoj kev, lossis subscript hu rov qab nil.
Pom zoo:
Dab tsi yog qhov sib txawv loj ntawm kev txheeb xyuas qhov yuam kev thiab kev kho cov lej yuam kev?
Ob qhov kev tshawb nrhiav qhov yuam kev thiab kev kho qhov yuam kev yuav tsum muaj qee qhov ntawm cov ntaub ntawv rov qab xa mus nrog cov ntaub ntawv tiag tiag; kev kho yuav tsum muaj ntau tshaj li kev tshawb nrhiav. Parity bits yog ib txoj hauv kev yooj yim rau kev tshawb nrhiav qhov yuam kev. Ib qho parity me ntsis yog ib qho ntxiv me ntsis xa nrog cov ntaub ntawv uas tsuas yog 1-ntsis suav ntawm cov ntaub ntawv
Kev xaiv tsa luv luv thiab kev xaiv tsa ntev yog dab tsi?
Kev xaiv tsa yog cov txheej txheem los ntawm cov neeg thov kev pabcuam rau cov ntaub ntawv tshiab tsis tu ncua. Hauv cov ntsiab lus yooj yim, Shortpolling yog AJAX-raws li timer uas hu rau ntawm qhov ncua sij hawm ncua sij hawm ntev yog raws li Comet (piv txwv li server yuav xa cov ntaub ntawv rau tus neeg siv khoom thaum lub server tshwm sim nrog nodelay)
Dab tsi yog kev xaiv khi Swift?
Koj siv qhov kev xaiv khij nyiab los xyuas seb qhov kev xaiv muaj tus nqi lossis tsis yog. Yog hais tias nws muaj ib tug nqi, unwrap nws thiab muab tso rau hauv ib ntus tas li los yog txawv txav
Dab tsi yog qhov sib txawv ntawm lub thawv thiab lub thawv ntawv thiab lub thawv ntawv yog dab tsi?
Ib lub thawv thiab cov ntawv nplawm (qee zaum hu ua boxplot) yog ib daim duab uas nthuav tawm cov ntaub ntawv los ntawm tsib lub ntsiab lus. Nyob rau hauv ib lub thawv thiab whisker zajlus: qhov kawg ntawm lub thawv yog lub sab sauv thiab sab quartiles, yog li lub thawv spans lub interquartile ntau yam. qhov nruab nrab yog cim los ntawm ib txoj kab ntsug hauv lub thawv
Dab tsi yog qhov zoo sib xws thiab qhov txawv ntawm relays thiab PLC yog dab tsi?
Relays yog electro-mechanical keyboards uas muaj coil thiab ob hom kev sib cuag uas tsis yog NO & NC. Tab sis Programmable Logic Controller, PLC yog lub khoos phis tawj me uas tuaj yeem txiav txim siab raws li qhov kev zov me nyuam thiab nws cov tswv yim & tso tawm