python - What is an ElementTree object exactly, and how can I get data from it? -

i'm trying teach myself how parse xml. i've read lxml tutorials, they're hard understand. far, can do:

>>> lxml import etree >>> xml=etree.parse('ham.xml') >>> xml <lxml.etree._elementtree object @ 0x118de60> 

but how can data object? can't indexed xml[0], , can't iterated over.

more specifically, i'm using this xml file , i'm trying extract, say, between <l> tags that's surrounded <sp> tags contain, say, barnardo attribute.

it elementtree element object.

you can @ lxml api documentation, has lxml.etree._element page. page tells every single attribute , method on class ever want know about.

i'd start reading lxml.etree tutorial, however.

if element cannot indexed, however, empty tag, , there no child nodes retrieve.

to find lines bernardo, xpath expression needed, namespace map. doesn't matter prefix use, long non-empty string lxml map correct namespace url:

nsmap = {'s': 'http://www.tei-c.org/ns/1.0'}  line in tree.xpath('.//s:sp[@who="barnardo"]/s:l/text()', namespaces=nsmap):     print line.strip() 

this extracts text in <l> elements contained in <sp who="barnardo"> tags. note s: prefixes on tag names, nsmap dictionary tells lxml namespace use. printed these without surrounding whitespace.

for sample document, gives:

>>> line in tree.xpath('.//s:sp[@who="barnardo"]/s:l/text()', namespaces=nsmap): ...     print line.strip() ...  who's there? long live king! he. 'tis struck twelve; thee bed, francisco. have had quiet guard? well, night. if meet horatio , marcellus, rivals of watch, bid them make haste. say, what, horatio there? welcome, horatio: welcome, marcellus. have seen nothing. sit down awhile; , let once again assail ears, fortified against our story have 2 nights seen. last night of all, when yond same star that's westward pole had made course illume part of heaven burns, marcellus , myself, bell beating one,  in same figure, king that's dead. looks 'a not king? mark it, horatio. spoke to. see, stalks away! how now, horatio! tremble , pale: not more fantasy? think on't? think no other e'en so: may sort portentous figure comes armed through our watch; king , question of these wars. 'tis here! speak, when cock crew.