Cov txheej txheem:
Video: Koj ua li cas piv cov nqi ntawm daim ntawv qhia?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Txoj hauv kev kom yog los sib piv cov duab qhia txog tus nqi sib npaug yog:
- Xyuas tias cov daim ntawv qhia yog tib qhov loj (!)
- Tau cov yuam sij ntawm ib qho daim ntawv qhia .
- Rau txhua tus yuam sij los ntawm qhov teeb tsa koj tau rov qab, xyuas tias qhov tus nqi tau txais los ntawm txhua tus daim ntawv qhia rau tus yuam sij ntawd yog tib yam (yog tias tus yuam sij tsis tuaj ntawm ib qho daim ntawv qhia , qhov ntawd yog tag nrho kev tsis sib haum xeeb)
Tsis tas li ntawd, koj piv Hashmaps li cas?
Yog peb xav tau piv hashmaps los ntawm cov yuam sij i.e. ob hashmaps yuav sib npaug yog tias lawv muaj cov yuam sij tib yam, peb tuaj yeem siv HashMap . keySet() muaj nuj nqi. Nws rov qab tag nrho daim ntawv qhia yuam sij hauv HashSet. Peb ua tau piv lub hashset ntawm cov yuam sij rau ob daim ntawv qhia siv Set.
Ib yam li ntawd, peb puas tuaj yeem sib piv ob daim duab qhia hauv C ++? Cov daim ntawv qhia ::key_comp() yog ib qho haujlwm hauv STL hauv C++ uas xa rov qab ib daim qauv ntawm kev sib piv khoom siv los ntawm lub thawv uas piv yuam sij. Rov qab tus nqi: Txoj kev no rov qab cov kev sib piv khoom siv los ntawm lub thawv uas piv yuam sij. // C++ program los ua qauv qhia daim ntawv qhia ::key_comp().
Tsis tas li, koj ua li cas piv ob Arraylists?
Koj ua tau piv ob array npe siv cov equals() method of the ArrayList chav kawm, txoj kev no lees txais cov npe khoom raws li qhov ntsuas, piv nrog cov khoom tam sim no, nyob rau hauv rooj plaub ntawm qhov sib tw nws rov qab muaj tseeb thiab yog tias tsis yog nws rov qab tsis tseeb.
Koj piv cov khoom hauv Java li cas?
Yuav tau piv ob Java khoom ntawm tib chav kawm qhov boolean sib npaug ( Yam khoom obj) txoj kev yuav tsum tau overriden thiab siv los ntawm chav kawm. Tus neeg siv txiav txim siab seb qhov twg yuav tsum sib npaug los xav txog ob khoom kom sib npaug.
Pom zoo:
Daim ntawv qhia ncuav qab zib piav qhia nrog piv txwv yog dab tsi?
Cov kab kos ncuav qab zib yog siv hauv kev tuav cov ntaub ntawv thiab yog cov kab kos kab sib faib ua ntu uas txhua tus sawv cev rau tus nqi. Daim duab ncuav qab zib tau muab faib ua ntu (lossis 'slices') los sawv cev rau qhov sib txawv ntawm qhov ntau thiab tsawg. Piv txwv li, nyob rau hauv daim ntawv qhia ncuav qab zib no, lub voj voog sawv cev rau tag nrho cov chav kawm
Koj sau cov ntaub ntawv nthuav qhia li cas rau daim ntawv tshawb fawb?
Cov kauj ruam rau kev nthuav qhia thiab tshuaj xyuas cov ntaub ntawv: Teeb lub hom phiaj ntawm txoj kev kawm thiab ua ib daim ntawv teev cov ntaub ntawv yuav tsum tau sau thiab nws hom. Sau / tau txais cov ntaub ntawv los ntawm qhov chaw thawj lossis thib ob. Hloov cov hom ntaub ntawv, piv txwv li, lub rooj, maps, graphs, thiab lwm yam nyob rau hauv hom xav tau
Yuav ua li cas koj tsim ib daim ntawv qhia uas qhia peb lub hlis twg kev muag khoom los ntawm ib cheeb tsam hauv Excel 2016?
Manually tsim PivotTable Nyem ib lub xovtooj ntawm cov ntaub ntawv los yog cov lus ntau. Mus rau Insert> Pom Zoo PivotTable. Excel txheeb xyuas koj cov ntaub ntawv thiab nthuav qhia koj nrog ntau txoj kev xaiv, zoo li hauv qhov piv txwv no siv cov ntaub ntawv siv nyiaj hauv tsev. Xaiv lub PivotTable uas zoo tshaj rau koj thiab nias OK
Vim li cas kem taw qhia cov ntaub ntawv khaws cia ua cov ntaub ntawv nkag ntawm disks sai dua li kab qhia cov ntaub ntawv khaws cia?
Kem oriented databases (aka columnar databases) yog qhov tsim nyog rau kev ntsuas kev ua haujlwm ntau dua vim tias cov ntaub ntawv hom ntawv (kem hom) qiv nws tus kheej kom nrawm dua cov lus nug ua - scans, aggregation thiab lwm yam. Ntawm qhov tod tes, kab oriented databases khaws ib kab (thiab tag nrho nws. kab) contiguously
Tus neeg teb xov tooj sib piv twg yog siv los sib piv tus nqi rau txhua tus nqi xa rov qab los ntawm subquery?
TAG NRHO tus neeg teb xov tooj yog siv los xaiv tag nrho cov tuples ntawm SELECT STATEMENT. Nws kuj yog siv los sib piv tus nqi rau txhua tus nqi hauv lwm tus nqi los yog tshwm sim los ntawm ib qho lus nug. TAG NRHO tus neeg teb xov tooj rov qab TRUE yog tias tag nrho cov lus nug tseem ceeb ua tau raws li qhov xwm txheej