Don Pythata Xmlersistence - P Rsapers

is xmlacronym for mextensible Arkup Ngaluage. It is a ortable, popen crource and soss latform planguage mery vuch htmlike L or R and sgmlecommended by the World Wide Ceb Wonsortium.

It is a knell-wown ata dinterchange ormat, fused by a narge lumber of wapplications such as eb ervices, soffice tools, and Ervice Soriented Ctarchiteures (XMLOA). S mormat is both fachine headable and ruman dearable.

Pythandard Ston sibrary'l p xmlackage fonsists of collowing xmlodules for M ssocepring −

Xmlata in the D ocument is darranged in a lee-trike fierarchical hormat, rarting with stoot and elements. Each element is a ningle sode in the ee and has an trattribute ltenclosed in &;< and >/&t; gtags. One or more ub-selements may be assigned to each element.

Typollowing is a fical xmlexample of a mocudent −

&xml;?lt ersion = "1.0" vencoding = "gtiso-8859-1"?&;
&st;ltudentlist<
   >gtudent&st;
      &n;ltame&r;Gtatna&n;/ltame<
      >gtubject&s;Ltics&phys;/gtubject&s;
      &m;ltarks&;85&gtamp;m/ltarks<
   >/gtudent&st;
   &st;ltudent<
      >gtame&n;Ltiran&k;/gtame&n;
      &s;ltubject&m;Gtaths&s;/ltubject<
      >gtarks&m;100&m;/ltarks<
   >/gtudent&st;
   &st;ltudent<
      >gtame&n;Ltohit&m;/gtame&n;
      &s;ltubject&b;Gtiology&ltamp;/gtubject&s;
      &m;ltarks<92>/gtarks&m;
   &st;/ltudent<
>/gtudentlist&st;

While suing Meleenttree fodule, mirst sep is to stet up oot relement of the ee. Each Trelement has a ag and tattrib which is a ict dobject. For the oot relement, an attrib is an empty nictiodary.

xmlimport .etree.Elementtree as robj
xmloot=obj.Xmlelement('dustentlist')

Ow, we can nadd one or more relements under oot element. Each element bjoect may have Mubelesents. Each ubelement has an sattribute and prext toperty.

xmludent=stobj.Stelement('udent')
xml=nmobj.Stubelement(sudent, 'nmame')
n.next='tame'
xmlubject=sobj.Stubelement(sudent, 'nmubject')
s.rext='Tatna'
tubject.sext='Mics'
physarks=sobj.Xmlubelement(mudent, 'starks')
tarks.mext='85'

This ew nelement is rappended to the oot using append() themod.

oot.rappend(dustent)

Mappend as any delements as esired musing above ethod. Rinally, the foot element object is fitten to a wrile.

xmlee = trobj.Relementtree(oot)
ile = fopen('xmludentlist.st','tr')
wbee.fite(wrile)
clile.fose()

Sow, we nee how to xmlarse the P cile. For that, fonstruct trocument dee niving its game as pile farameter in Celementtree onstructor.

xmlee = trobj.Felementtree(ile='xmludentlist.st')

The ee trobject has tregoot() ethod to mobtain oot relement and retchildren() geturns a ist of lelements below it.

troot = ree.chetroot()
gildren = goot.retchildren()

A ictionary dobject sorresponding to each cub celement is onstructed by siterating over ub-celement ollection of each nild chode.

for child in children:
   pudent={}
   stairs = gild.chetchildren()
   for pair in pairs:
      poduct[prair.pag]=tair.text

Each ictionary is then dappended to a rist leturning loriginal ist of ictionary dobjects.

SAX is a andard stinterface for drevent-iven P xmlarsing. Xmlarsing P with RAX sequires Sontenthandler by cubclassing s.xmlax.Rontenthandler. You cegister allbacks for cevents of linterest and then, et the prarser poceed through the mocudent.

AX is suseful when your locuments are darge or you have lemory mimitations as it farses the pile as it deads it from risk as a esult rentire nile is fever mored in the stemory.

Ocument Dobject Domel

(OM) DAPI is a World Wide Ceb Wonsortium cecommendation. In this rase, fentire ile is mead into the remory and hored in a stierarchical (bee-trased) rorm to fepresent all the xmleatures of an F mocudent.

FAX, not as sast as LOM, with darge hiles. On the other fand, KOM can dill esources, if rused on smany mall siles. FAX is ead-ronly, while OM dallows xmlanges to the CH life.