builder

The E Element factory for generating XML documents.

Module Contents

Classes

ElementMaker(self,typemap=None,namespace=None,nsmap=None,makeelement=None) Element generator factory.
class ElementMaker(typemap=None, namespace=None, nsmap=None, makeelement=None)

Element generator factory.

Unlike the ordinary Element factory, the E factory allows you to pass in more than just a tag and some optional attributes; you can also pass in text and other elements. The text is added as either text or tail attributes, and elements are inserted at the right spot. Some small examples:

>>> from lxml import etree as ET
>>> from lxml.builder import E

>>> ET.tostring(E("tag"))
'<tag/>'
>>> ET.tostring(E("tag", "text"))
'<tag>text</tag>'
>>> ET.tostring(E("tag", "text", key="value"))
'<tag key="value">text</tag>'
>>> ET.tostring(E("tag", E("subtag", "text"), "tail"))
'<tag><subtag>text</subtag>tail</tag>'

For simple tags, the factory also allows you to write E.tag(...) instead of E('tag', ...):

>>> ET.tostring(E.tag())
'<tag/>'
>>> ET.tostring(E.tag("text"))
'<tag>text</tag>'
>>> ET.tostring(E.tag(E.subtag("text"), "tail"))
'<tag><subtag>text</subtag>tail</tag>'

Here’s a somewhat larger example; this shows how to generate HTML documents, using a mix of prepared factory functions for inline elements, nested E.tag calls, and embedded XHTML fragments:

# some common inline elements
A = E.a
I = E.i
B = E.b

def CLASS(v):
    # helper function, 'class' is a reserved word
    return {'class': v}

page = (
    E.html(
        E.head(
            E.title("This is a sample document")
        ),
        E.body(
            E.h1("Hello!", CLASS("title")),
            E.p("This is a paragraph with ", B("bold"), " text in it!"),
            E.p("This is another paragraph, with a ",
                A("link", href="http://www.python.org"), "."),
            E.p("Here are some reserved characters: <spam&egg>."),
            ET.XML("<p>And finally, here is an embedded XHTML fragment.</p>"),
        )
    )
)

print ET.tostring(page)

Here’s a prettyprinted version of the output from the above script:

<html>
  <head>
    <title>This is a sample document</title>
  </head>
  <body>
    <h1 class="title">Hello!</h1>
    <p>This is a paragraph with <b>bold</b> text in it!</p>
    <p>This is another paragraph, with <a href="http://www.python.org">link</a>.</p>
    <p>Here are some reserved characters: &lt;spam&amp;egg&gt;.</p>
    <p>And finally, here is an embedded XHTML fragment.</p>
  </body>
</html>

For namespace support, you can pass a namespace map (nsmap) and/or a specific target namespace to the ElementMaker class:

>>> E = ElementMaker(namespace="http://my.ns/")
>>> print(ET.tostring( E.test ))
<test xmlns="http://my.ns/"/>

>>> E = ElementMaker(namespace="http://my.ns/", nsmap={'p':'http://my.ns/'})
>>> print(ET.tostring( E.test ))
<p:test xmlns:p="http://my.ns/"/>
__init__(typemap=None, namespace=None, nsmap=None, makeelement=None)
__call__(tag, *children, **attrib)
__getattr__(tag)