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I-Web Scraping nge-Expert Semalt

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I-Web scraping, eyaziwa nangokuvuna iwebhu, yindlela yokusetyenziswa khipha idatha kwiwebhusayithi. Isofthiwe yokuvuna yeWeb ingafikelela kwiwebhu ngokuchanekileyo isebenzisa i-HTTP okanye isiphequluli sewebhu. Nangona inkqubo ingasetyenziswa ngokusetyenziswa ngumsebenzisi wesofthiwe, ubuchule ngokubanzi bubandakanya inkqubo eyenziwe ngokuzenzekelayo isebenzise ngokusebenzisa umgca wewebhu okanye ibhotile.

I-Web scraping yinkqubo xa idatha echanekileyo ikopiwe kwiwebhu ibe yindawo egciniweyo yokuhlaziywa kunye nokufunyanwa. Kuquka ukulanda iphepha lewebhu kunye nokukhipha umxholo walo. Umxholo wephepha unokwenziwa, uphendelwe, uhlengahlengiswe kwaye idatha yayo ikopiwe kwifowuni yokugcina indawo.

Amaphepha eWebhu awakhiwe ngokubanzi ngeelwimi ezisetyenziswe ngetekisi ezifana ne-XHTML kunye ne-HTML, zombini equlethe ubuninzi beenkcukacha ezisebenzayo ngendlela yombhalo. Nangona kunjalo, ezininzi zewebhu zize zenzelwe abasebenzisi bokuphela komntu kwaye kungekhona ukusetyenziswa ngokuzenzekelayo. Esi sizathu sokuba kutheni isofthiwe yenziwe.

Kukho ubuchule obuninzi obungasetyenziselwa ukwenziwa kwewebhu ngokufanelekileyo. Ezinye zazo zichazwe ngezantsi:

1. I-Copy-and-paste

Ngamanye amaxesha, kweso sixhobo (even) sewebhu esingcono ukuchaneka nokusebenza kwekhompyutheni yomntu-kunye nokunamathisela..Oku kusebenza kakhulu kwiimeko apho iiwebhusayithi zibeka imingcele yokuthintela ukuchithwa komatshini.

2. Ukubambisana Kwimizekelo yePatheni

Le ndlela iyindlela elula kodwa enamandla esetyenziselwa ukukhipha idatha kumaphepha ewebhu. Ingase isekelwe kumyalelo we-UNIX grep okanye nje isixhobo sokubonisa inkqubo yolwimi olunikeziweyo, umzekelo, iPython okanye iPerl.

3. I-HTTP Programming

I-HTTP Inkqubo ingasetyenziselwa kumanqanaba amabini e-static kunye anamandla. Idata ikhishwa ngokuthumela izicelo ze-HTTP kwisiphakeli sewebhu esisekude ngelixa isebenzisa inkqubo yesikhokelo.

4. I-HTML Inkcazo

(ezininzi) iiwebhsayithi zivame ukuba neqoqo elibanzi lamaphepha adalwe ngokuzenzekelayo ukusuka kwisiseko esisezantsi kwisiseko sedata. Apha, idatha enomxholo ofanayo ikhowudiwe kumaphepha afanayo. Kwi-HTML ukuxhaswa, inkqubo ngokubanzi ibona itemplate enjalo kwimithombo ethile yolwazi, ibuyisela oko iqulethe kwaye iguqulele kwifom echaphazelekayo, ebizwa ngokuba yi-wrapper.

5. I-DOM ukuxhaswa

Kule ndlela, inkqubo ifakwe kwisiphequluli esipheleleyo sewebhu njengesi-Mozilla Firefox okanye i-Intanethi Explorer ukufumana umxholo onamandla oveliswe ngumgca wecala lomxhasi. Ezi pheqululwazi zingaphinda zidibanise namaphepha ewebhu kwi-DOM tree ngokuxhomekeke kwiiprogram ezinokukhupha iindawo zamaphepha.

6. Ukumenyezelwa kweSannotation Annotation

Amaphepha enu uzimisele ukuwaqhawula angamkela ukuhamba kweempawu kunye nezichasiselo okanye imethadatha, engasetyenziselwa ukufumana iimboniselo zeedatha ezithile. Ukuba ezi ngcaciso zifakwe kumaphepha, le nkqubo ingabonwa njengeyona nto ekhethekileyo ye-DOM. Ezi zichasiselo zingabuye ziququzelelwe kwicala lokucwangcisa, kwaye zigcinwe kwaye zilawulwe ngokwahlukileyo kumakhasi ewebhu. Ivumela abaxhamli ukuba bafumane i-schema yedatha kunye nemiyalelo esuka kuloluhlu ngaphambi kokutshitshisa amaphepha.

December 6, 2017
I-Web Scraping nge-Expert Semalt
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