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colorize interactive shell examples
This commit is contained in:
Mark Pilgrim
@@ -254,11 +254,11 @@ mark{display:inline}
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<p class=d>[<a href=examples/feed.xml>download <code>feed.xml</code></a>]
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<pre class=screen>
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<a><samp class=p>>>> </samp><kbd>import xml.etree.ElementTree as etree</kbd> <span class=u>①</span></a>
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<a><samp class=p>>>> </samp><kbd>tree = etree.parse('examples/feed.xml')</kbd> <span class=u>②</span></a>
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<a><samp class=p>>>> </samp><kbd>root = tree.getroot()</kbd> <span class=u>③</span></a>
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<a><samp class=p>>>> </samp><kbd>root</kbd> <span class=u>④</span></a>
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<samp><Element {http://www.w3.org/2005/Atom}feed at cd1eb0></samp></pre>
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<a><samp class=p>>>> </samp><kbd class=pp>import xml.etree.ElementTree as etree</kbd> <span class=u>①</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>tree = etree.parse('examples/feed.xml')</kbd> <span class=u>②</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>root = tree.getroot()</kbd> <span class=u>③</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>root</kbd> <span class=u>④</span></a>
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<samp class=pp><Element {http://www.w3.org/2005/Atom}feed at cd1eb0></samp></pre>
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<ol>
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<li>The ElementTree library is part of the Python standard library, in <code>xml.etree.ElementTree</code>.
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<li>The primary entry point for the ElementTree library is the <code>parse()</code> function, which can take a filename or a file-like object [FIXME xref]. This function parses the entire document at once. If memory is tight, there are ways to <a href=http://effbot.org/zone/element-iterparse.htm>parse an <abbr>XML</abbr> document incrementally instead</a>.
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@@ -276,14 +276,14 @@ mark{display:inline}
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<pre class=screen>
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# continued from the previous example
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<a><samp class=p>>>> </samp><kbd>root.tag</kbd> <span class=u>①</span></a>
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<samp>'{http://www.w3.org/2005/Atom}feed'</samp>
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<a><samp class=p>>>> </samp><kbd>len(root)</kbd> <span class=u>②</span></a>
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<samp>8</samp>
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<a><samp class=p>>>> </samp><kbd>for child in root:</kbd> <span class=u>③</span></a>
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<a><samp class=p>... </samp><kbd> print(child)</kbd> <span class=u>④</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>root.tag</kbd> <span class=u>①</span></a>
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<samp class=pp>'{http://www.w3.org/2005/Atom}feed'</samp>
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<a><samp class=p>>>> </samp><kbd class=pp>len(root)</kbd> <span class=u>②</span></a>
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<samp class=pp>8</samp>
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<a><samp class=p>>>> </samp><kbd class=pp>for child in root:</kbd> <span class=u>③</span></a>
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<a><samp class=p>... </samp><kbd class=pp> print(child)</kbd> <span class=u>④</span></a>
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<samp class=p>... </samp>
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<samp><Element {http://www.w3.org/2005/Atom}title at e2b5d0>
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<samp class=pp><Element {http://www.w3.org/2005/Atom}title at e2b5d0>
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<Element {http://www.w3.org/2005/Atom}subtitle at e2b4e0>
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<Element {http://www.w3.org/2005/Atom}id at e2b6c0>
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<Element {http://www.w3.org/2005/Atom}updated at e2b6f0>
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@@ -306,18 +306,18 @@ mark{display:inline}
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<pre class=screen>
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# continuing from the previous example
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<a><samp class=p>>>> </samp><kbd>root.attrib</kbd> <span class=u>①</span></a>
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<samp>{'{http://www.w3.org/XML/1998/namespace}lang': 'en'}</samp>
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<a><samp class=p>>>> </samp><kbd>root[4]</kbd> <span class=u>②</span></a>
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<samp><Element {http://www.w3.org/2005/Atom}link at e181b0></samp>
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<a><samp class=p>>>> </samp><kbd>root[4].attrib</kbd> <span class=u>③</span></a>
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<samp>{'href': 'http://diveintomark.org/',
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<a><samp class=p>>>> </samp><kbd class=pp>root.attrib</kbd> <span class=u>①</span></a>
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<samp class=pp>{'{http://www.w3.org/XML/1998/namespace}lang': 'en'}</samp>
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<a><samp class=p>>>> </samp><kbd class=pp>root[4]</kbd> <span class=u>②</span></a>
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<samp class=pp><Element {http://www.w3.org/2005/Atom}link at e181b0></samp>
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<a><samp class=p>>>> </samp><kbd class=pp>root[4].attrib</kbd> <span class=u>③</span></a>
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<samp class=pp>{'href': 'http://diveintomark.org/',
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'type': 'text/html',
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'rel': 'alternate'}</samp>
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<a><samp class=p>>>> </samp><kbd>root[3]</kbd> <span class=u>④</span></a>
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<samp><Element {http://www.w3.org/2005/Atom}updated at e2b4e0></samp>
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<a><samp class=p>>>> </samp><kbd>root[3].attrib</kbd> <span class=u>⑤</span></a>
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<samp>{}</samp></pre>
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<a><samp class=p>>>> </samp><kbd class=pp>root[3]</kbd> <span class=u>④</span></a>
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<samp class=pp><Element {http://www.w3.org/2005/Atom}updated at e2b4e0></samp>
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<a><samp class=p>>>> </samp><kbd class=pp>root[3].attrib</kbd> <span class=u>⑤</span></a>
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<samp class=pp>{}</samp></pre>
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<ol>
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<li>The <code>attrib</code> property is a dictionary of the element’s attributes. The original markup here was <code><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'></code>. The <code>xml:</code> prefix refers to a built-in namespace that every <abbr>XML</abbr> document can use without declaring it.
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<li>The fifth child — <code>[4]</code> in a <code>0</code>-based list — is the <code>link</code> element.
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@@ -333,19 +333,19 @@ mark{display:inline}
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<p>So far, we’ve worked with this <abbr>XML</abbr> document “from the top down,” starting with the root element, getting its child elements, and so on throughout the document. But many uses of <abbr>XML</abbr> require you to find specific elements. Etree can do that, too.
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<pre class=screen>
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<samp class=p>>>> </samp><kbd>import xml.etree.ElementTree as etree</kbd>
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<samp class=p>>>> </samp><kbd>tree = etree.parse('examples/feed.xml')</kbd>
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<samp class=p>>>> </samp><kbd>root = tree.getroot()</kbd>
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<a><samp class=p>>>> </samp><kbd>root.findall('{http://www.w3.org/2005/Atom}entry')</kbd> <span class=u>①</span></a>
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<samp>[<Element {http://www.w3.org/2005/Atom}entry at e2b4e0>,
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<samp class=p>>>> </samp><kbd class=pp>import xml.etree.ElementTree as etree</kbd>
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<samp class=p>>>> </samp><kbd class=pp>tree = etree.parse('examples/feed.xml')</kbd>
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<samp class=p>>>> </samp><kbd class=pp>root = tree.getroot()</kbd>
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<a><samp class=p>>>> </samp><kbd class=pp>root.findall('{http://www.w3.org/2005/Atom}entry')</kbd> <span class=u>①</span></a>
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<samp class=pp>[<Element {http://www.w3.org/2005/Atom}entry at e2b4e0>,
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<Element {http://www.w3.org/2005/Atom}entry at e2b510>,
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<Element {http://www.w3.org/2005/Atom}entry at e2b540>]</samp>
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<samp class=p>>>> </samp><kbd>root.tag</kbd>
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<samp>'{http://www.w3.org/2005/Atom}feed'</samp>
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<a><samp class=p>>>> </samp><kbd>root.findall('{http://www.w3.org/2005/Atom}feed')</kbd> <span class=u>②</span></a>
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<samp>[]</samp>
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<a><samp class=p>>>> </samp><kbd>root.findall('{http://www.w3.org/2005/Atom}author')</kbd> <span class=u>③</span></a>
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<samp>[]</samp></pre>
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<samp class=p>>>> </samp><kbd class=pp>root.tag</kbd>
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<samp class=pp>'{http://www.w3.org/2005/Atom}feed'</samp>
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<a><samp class=p>>>> </samp><kbd class=pp>root.findall('{http://www.w3.org/2005/Atom}feed')</kbd> <span class=u>②</span></a>
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<samp class=pp>[]</samp>
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<a><samp class=p>>>> </samp><kbd class=pp>root.findall('{http://www.w3.org/2005/Atom}author')</kbd> <span class=u>③</span></a>
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<samp class=pp>[]</samp></pre>
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<ol>
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<li>The <code>findall()</code> method finds child elements that match a specific query. (More on the query format in a minute.)
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<li>Each element — including the root element, but also child elements — has a <code>findall()</code> method. It finds all matching elements among the element’s children. But why aren’t there any results? Although it may not be obvious, this particular query only searches the element’s children. Since the root <code>feed</code> element has no child named <code>feed</code>, this query returns an empty list.
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@@ -353,12 +353,12 @@ mark{display:inline}
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</ol>
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<pre class=screen>
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<a><samp class=p>>>> </samp><kbd>tree.findall('{http://www.w3.org/2005/Atom}entry')</kbd> <span class=u>①</span></a>
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<samp>[<Element {http://www.w3.org/2005/Atom}entry at e2b4e0>,
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<a><samp class=p>>>> </samp><kbd class=pp>tree.findall('{http://www.w3.org/2005/Atom}entry')</kbd> <span class=u>①</span></a>
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<samp class=pp>[<Element {http://www.w3.org/2005/Atom}entry at e2b4e0>,
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<Element {http://www.w3.org/2005/Atom}entry at e2b510>,
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<Element {http://www.w3.org/2005/Atom}entry at e2b540>]</samp>
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<a><samp class=p>>>> </samp><kbd>tree.findall('{http://www.w3.org/2005/Atom}author')</kbd> <span class=u>②</span></a>
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<samp>[]</samp>
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<a><samp class=p>>>> </samp><kbd class=pp>tree.findall('{http://www.w3.org/2005/Atom}author')</kbd> <span class=u>②</span></a>
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<samp class=pp>[]</samp>
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</pre>
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<ol>
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<li>For convenience, the <code>tree</code> object (returned from the <code>etree.parse()</code> function) has several methods that mirror the methods on the root element. The results are the same as if you had called the <code>tree.getroot().findall()</code> method.
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@@ -368,26 +368,26 @@ mark{display:inline}
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<p>There <em>is</em> a way to search for <em>descendant</em> elements, <i>i.e.</i> children, grandchildren, and any element at any nesting level.
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<pre class=screen>
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<a><samp class=p>>>> </samp><kbd>all_links = tree.findall('//{http://www.w3.org/2005/Atom}link')</kbd> <span class=u>①</span></a>
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<samp class=p>>>> </samp><kbd>all_links</kbd>
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<samp>[<Element {http://www.w3.org/2005/Atom}link at e181b0>,
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<a><samp class=p>>>> </samp><kbd class=pp>all_links = tree.findall('//{http://www.w3.org/2005/Atom}link')</kbd> <span class=u>①</span></a>
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<samp class=p>>>> </samp><kbd class=pp>all_links</kbd>
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<samp class=pp>[<Element {http://www.w3.org/2005/Atom}link at e181b0>,
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<Element {http://www.w3.org/2005/Atom}link at e2b570>,
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<Element {http://www.w3.org/2005/Atom}link at e2b480>,
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<Element {http://www.w3.org/2005/Atom}link at e2b5a0>]</samp>
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<a><samp class=p>>>> </samp><kbd>all_links[0].attrib</kbd> <span class=u>②</span></a>
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<samp>{'href': 'http://diveintomark.org/',
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<a><samp class=p>>>> </samp><kbd class=pp>all_links[0].attrib</kbd> <span class=u>②</span></a>
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<samp class=pp>{'href': 'http://diveintomark.org/',
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'type': 'text/html',
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'rel': 'alternate'}</samp>
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<a><samp class=p>>>> </samp><kbd>all_links[1].attrib</kbd> <span class=u>③</span></a>
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<samp>{'href': 'http://diveintomark.org/archives/2009/03/27/dive-into-history-2009-edition',
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<a><samp class=p>>>> </samp><kbd class=pp>all_links[1].attrib</kbd> <span class=u>③</span></a>
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<samp class=pp>{'href': 'http://diveintomark.org/archives/2009/03/27/dive-into-history-2009-edition',
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'type': 'text/html',
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'rel': 'alternate'}</samp>
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<samp class=p>>>> </samp><kbd>all_links[2].attrib</kbd>
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<samp>{'href': 'http://diveintomark.org/archives/2009/03/21/accessibility-is-a-harsh-mistress',
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<samp class=p>>>> </samp><kbd class=pp>all_links[2].attrib</kbd>
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<samp class=pp>{'href': 'http://diveintomark.org/archives/2009/03/21/accessibility-is-a-harsh-mistress',
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'type': 'text/html',
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'rel': 'alternate'}</samp>
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<samp class=p>>>> </samp><kbd>all_links[3].attrib</kbd>
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<samp>{'href': 'http://diveintomark.org/archives/2008/12/18/give-part-1-container-formats',
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<samp class=p>>>> </samp><kbd class=pp>all_links[3].attrib</kbd>
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<samp class=pp>{'href': 'http://diveintomark.org/archives/2008/12/18/give-part-1-container-formats',
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'type': 'text/html',
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'rel': 'alternate'}</samp></pre>
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<ol>
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@@ -400,16 +400,16 @@ mark{display:inline}
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<pre class=screen>
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# continuing from the previous example
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<a><samp class=p>>>> </samp><kbd>it = tree.getiterator('{http://www.w3.org/2005/Atom}link')</kbd> <span class=u>①</span></a>
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<a><samp class=p>>>> </samp><kbd>next(it)</kbd> <span class=u>②</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>it = tree.getiterator('{http://www.w3.org/2005/Atom}link')</kbd> <span class=u>①</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>next(it)</kbd> <span class=u>②</span></a>
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<Element {http://www.w3.org/2005/Atom}link at 122f1b0>
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<samp class=p>>>> </samp><kbd>next(it)</kbd>
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<samp class=p>>>> </samp><kbd class=pp>next(it)</kbd>
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<Element {http://www.w3.org/2005/Atom}link at 122f1e0>
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<samp class=p>>>> </samp><kbd>next(it)</kbd>
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<samp class=p>>>> </samp><kbd class=pp>next(it)</kbd>
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<Element {http://www.w3.org/2005/Atom}link at 122f210>
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<samp class=p>>>> </samp><kbd>next(it)</kbd>
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<samp class=p>>>> </samp><kbd class=pp>next(it)</kbd>
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<Element {http://www.w3.org/2005/Atom}link at 122f1b0>
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<samp class=p>>>> </samp><kbd>next(it)</kbd>
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<samp class=p>>>> </samp><kbd class=pp>next(it)</kbd>
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<samp class=traceback>Traceback (most recent call last):
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File "<stdin>", line 1, in <module>
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StopIteration</samp></pre>
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@@ -427,11 +427,11 @@ StopIteration</samp></pre>
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<p><a href=http://codespeak.net/lxml/><code>lxml</code></a> is an open source third-party library that builds on the popular <a href=http://www.xmlsoft.org/>libxml2 parser</a>. It provides a 100% compatible ElementTree <abbr>API</abbr>, then extends it with full XPath support and a few other niceties. There are <a href=http://pypi.python.org/pypi/lxml/>installers available for Windows</a>; Linux users should always try to use distribution-specific tools like <code>yum</code> or <code>apt-get</code> to install precompiled binaries from their repositories. Otherwise you’ll need to <a href=http://codespeak.net/lxml/installation.html>install <code>lxml</code> manually</a>.
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<pre class=screen>
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<a><samp class=p>>>> </samp><kbd>from lxml import etree</kbd> <span class=u>①</span></a>
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<a><samp class=p>>>> </samp><kbd>tree = etree.parse('examples/feed.xml')</kbd> <span class=u>②</span></a>
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<a><samp class=p>>>> </samp><kbd>root = tree.getroot()</kbd> <span class=u>③</span></a>
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<a><samp class=p>>>> </samp><kbd>root.findall('{http://www.w3.org/2005/Atom}entry')</kbd> <span class=u>④</span></a>
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<samp>[<Element {http://www.w3.org/2005/Atom}entry at e2b4e0>,
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<a><samp class=p>>>> </samp><kbd class=pp>from lxml import etree</kbd> <span class=u>①</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>tree = etree.parse('examples/feed.xml')</kbd> <span class=u>②</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>root = tree.getroot()</kbd> <span class=u>③</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>root.findall('{http://www.w3.org/2005/Atom}entry')</kbd> <span class=u>④</span></a>
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<samp class=pp>[<Element {http://www.w3.org/2005/Atom}entry at e2b4e0>,
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<Element {http://www.w3.org/2005/Atom}entry at e2b510>,
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<Element {http://www.w3.org/2005/Atom}entry at e2b540>]</samp></pre>
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<ol>
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@@ -451,18 +451,18 @@ except ImportError:
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<p>But <code>lxml</code> is more than just a faster ElementTree. Its <code>findall()</code> method includes support for more complicated expressions.
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<pre class=screen>
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<a><samp class=p>>>> </samp><kbd>import lxml.etree</kbd> <span class=u>①</span></a>
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<samp class=p>>>> </samp><kbd>tree = lxml.etree.parse('examples/feed.xml')</kbd>
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<a><samp class=p>>>> </samp><kbd>tree.findall('//{http://www.w3.org/2005/Atom}*[@href]')</kbd> <span class=u>②</span></a>
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<a><samp class=p>>>> </samp><kbd class=pp>import lxml.etree</kbd> <span class=u>①</span></a>
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<samp class=p>>>> </samp><kbd class=pp>tree = lxml.etree.parse('examples/feed.xml')</kbd>
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<a><samp class=p>>>> </samp><kbd class=pp>tree.findall('//{http://www.w3.org/2005/Atom}*[@href]')</kbd> <span class=u>②</span></a>
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[<Element {http://www.w3.org/2005/Atom}link at eeb8a0>,
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<Element {http://www.w3.org/2005/Atom}link at eeb990>,
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<Element {http://www.w3.org/2005/Atom}link at eeb960>,
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<Element {http://www.w3.org/2005/Atom}link at eeb9c0>]
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<a><samp class=p>>>> </samp><kbd>tree.findall("//{http://www.w3.org/2005/Atom}*[@href='http://diveintomark.org/']")</kbd> <span class=u>③</span></a>
|
||||
<samp>[<Element {http://www.w3.org/2005/Atom}link at eeb930>]</samp>
|
||||
<samp class=p>>>> </samp><kbd>NS = '{http://www.w3.org/2005/Atom}'</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>tree.findall('//{NS}author[{NS}uri]'.format(NS=NS))</kbd> <span class=u>④</span></a>
|
||||
<samp>[<Element {http://www.w3.org/2005/Atom}author at eeba80>,
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>tree.findall("//{http://www.w3.org/2005/Atom}*[@href='http://diveintomark.org/']")</kbd> <span class=u>③</span></a>
|
||||
<samp class=pp>[<Element {http://www.w3.org/2005/Atom}link at eeb930>]</samp>
|
||||
<samp class=p>>>> </samp><kbd class=pp>NS = '{http://www.w3.org/2005/Atom}'</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>tree.findall('//{NS}author[{NS}uri]'.format(NS=NS))</kbd> <span class=u>④</span></a>
|
||||
<samp class=pp>[<Element {http://www.w3.org/2005/Atom}author at eeba80>,
|
||||
<Element {http://www.w3.org/2005/Atom}author at eebba0>]</samp></pre>
|
||||
<ol>
|
||||
<li>In this example, I’m going to <code>import lxml.etree</code> (instead of, say, <code>from lxml import etree</code>), to emphasize that these features are specific to <code>lxml</code>.
|
||||
@@ -474,16 +474,16 @@ except ImportError:
|
||||
<p>Not enough for you? <code>lxml</code> also integrates support for arbitrary XPath expressions. I’m not going to go into depth about XPath syntax; that could be a whole book unto itself! But I will show you how it integrates into <code>lxml</code>.
|
||||
|
||||
<pre class=screen>
|
||||
<samp class=p>>>> </samp><kbd>import lxml.etree</kbd>
|
||||
<samp class=p>>>> </samp><kbd>tree = lxml.etree.parse('examples/feed.xml')</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>NSMAP = {'atom': 'http://www.w3.org/2005/Atom'}</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>entries = tree.xpath("//atom:category[@term='accessibility']/..",</kbd> <span class=u>②</span></a>
|
||||
<samp class=p>... </samp><kbd> namespaces=NSMAP)</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>entries</kbd> <span class=u>③</span></a>
|
||||
<samp>[<Element {http://www.w3.org/2005/Atom}entry at e2b630>]</samp>
|
||||
<samp class=p>>>> </samp><kbd>entry = entries[0]</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>entry.xpath('./atom:title/text()', namespaces=nsmap)</kbd> <span class=u>④</span></a>
|
||||
<samp>['Accessibility is a harsh mistress']</samp></pre>
|
||||
<samp class=p>>>> </samp><kbd class=pp>import lxml.etree</kbd>
|
||||
<samp class=p>>>> </samp><kbd class=pp>tree = lxml.etree.parse('examples/feed.xml')</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>NSMAP = {'atom': 'http://www.w3.org/2005/Atom'}</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>entries = tree.xpath("//atom:category[@term='accessibility']/..",</kbd> <span class=u>②</span></a>
|
||||
<samp class=p>... </samp><kbd class=pp> namespaces=NSMAP)</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>entries</kbd> <span class=u>③</span></a>
|
||||
<samp class=pp>[<Element {http://www.w3.org/2005/Atom}entry at e2b630>]</samp>
|
||||
<samp class=p>>>> </samp><kbd class=pp>entry = entries[0]</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>entry.xpath('./atom:title/text()', namespaces=nsmap)</kbd> <span class=u>④</span></a>
|
||||
<samp class=pp>['Accessibility is a harsh mistress']</samp></pre>
|
||||
<ol>
|
||||
<li>To perform XPath queries on namespaced elements, you need to define a namespace prefix mapping. This is just a Python dictionary.
|
||||
<li>Here is an XPath query. The XPath expression searches for <code>category</code> elements (in the Atom namespace) that contain a <code>term</code> attribute with the value <code>accessibility</code>. But that’s not actually the query result. Look at the very end of the query string; did you notice the <code>/..</code> bit? That means “and then return the parent element of the <code>category</code> element you just found.” So this single XPath query will find all entries with a child element of <code><category term='accessibility'></code>.
|
||||
@@ -498,11 +498,11 @@ except ImportError:
|
||||
<p>Python’s support for <abbr>XML</abbr> is not limited to parsing existing documents. You can also create <abbr>XML</abbr> documents from scratch.
|
||||
|
||||
<pre class=screen>
|
||||
<samp class=p>>>> </samp><kbd>import xml.etree.ElementTree as etree</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>new_feed = etree.Element('{http://www.w3.org/2005/Atom}feed',</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>... </samp><kbd> attrib={'{http://www.w3.org/XML/1998/namespace}lang': 'en'})</kbd> <span class=u>②</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>print(etree.tostring(new_feed))</kbd> <span class=u>③</span></a>
|
||||
<samp><ns0:feed xmlns:ns0='http://www.w3.org/2005/Atom' xml:lang='en'/></samp></pre>
|
||||
<samp class=p>>>> </samp><kbd class=pp>import xml.etree.ElementTree as etree</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>new_feed = etree.Element('{http://www.w3.org/2005/Atom}feed',</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>... </samp><kbd class=pp> attrib={'{http://www.w3.org/XML/1998/namespace}lang': 'en'})</kbd> <span class=u>②</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>print(etree.tostring(new_feed))</kbd> <span class=u>③</span></a>
|
||||
<samp class=pp><ns0:feed xmlns:ns0='http://www.w3.org/2005/Atom' xml:lang='en'/></samp></pre>
|
||||
<ol>
|
||||
<li>To create a new element, instantiate the <code>Element</code> class. You pass the element name (namespace + local name) as the first argument. This statement creates a <code>feed</code> element in the Atom namespace. This will be our new document’s root element.
|
||||
<li>To add attributes to the newly created element, pass a dictionary of attribute names and values in the <var>attrib</var> argument. Note that the attribute name should be in the standard ElementTree format, <code>{<var>namespace</var>}<var>localname</var></code>.
|
||||
@@ -524,14 +524,14 @@ except ImportError:
|
||||
<p>The built-in ElementTree library does not offer this fine-grained control over serializing namespaced elements, but <code>lxml</code> does.
|
||||
|
||||
<pre class=screen>
|
||||
<samp class=p>>>> </samp><kbd>import lxml.etree</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>NSMAP = {None: 'http://www.w3.org/2005/Atom'}</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>new_feed = lxml.etree.Element('feed', nsmap=NSMAP)</kbd> <span class=u>②</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>print(lxml.etree.tounicode(new_feed))</kbd> <span class=u>③</span></a>
|
||||
<samp><feed xmlns='http://www.w3.org/2005/Atom'/></samp>
|
||||
<a><samp class=p>>>> </samp><kbd>new_feed.set('{http://www.w3.org/XML/1998/namespace}lang', 'en')</kbd> <span class=u>④</span></a>
|
||||
<samp class=p>>>> </samp><kbd>print(lxml.etree.tounicode(new_feed))</kbd>
|
||||
<samp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'/></samp></pre>
|
||||
<samp class=p>>>> </samp><kbd class=pp>import lxml.etree</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>NSMAP = {None: 'http://www.w3.org/2005/Atom'}</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>new_feed = lxml.etree.Element('feed', nsmap=NSMAP)</kbd> <span class=u>②</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>print(lxml.etree.tounicode(new_feed))</kbd> <span class=u>③</span></a>
|
||||
<samp class=pp><feed xmlns='http://www.w3.org/2005/Atom'/></samp>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>new_feed.set('{http://www.w3.org/XML/1998/namespace}lang', 'en')</kbd> <span class=u>④</span></a>
|
||||
<samp class=p>>>> </samp><kbd class=pp>print(lxml.etree.tounicode(new_feed))</kbd>
|
||||
<samp class=pp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'/></samp></pre>
|
||||
<ol>
|
||||
<li>To start, define a namespace mapping as a dictionary. Dictionary values are namespaces; dictionary keys are the desired prefix. Using <code>None</code> as a prefix effectively declares a default namespace.
|
||||
<li>Now you can pass the <code>lxml</code>-specific <var>nsmap</var> argument when you create an element, and <code>lxml</code> will respect the namespace prefixes you’ve defined.
|
||||
@@ -542,15 +542,15 @@ except ImportError:
|
||||
<p>Are <abbr>XML</abbr> documents limited to one element per document? No, of course not. You can easily create child elements, too.
|
||||
|
||||
<pre class=screen>
|
||||
<a><samp class=p>>>> </samp><kbd>title = lxml.etree.SubElement(new_feed, 'title',</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>... </samp><kbd> attrib={'type':'html'})</kbd> <span class=u>②</span></a>
|
||||
<samp class=p>>>> </samp><kbd>print(lxml.etree.tounicode(new_feed))</kbd>
|
||||
<samp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'><title type='html'/></feed></samp>
|
||||
<a><samp class=p>>>> </samp><kbd>title.text = 'dive into &hellip;'</kbd> <span class=u>③</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>print(lxml.etree.tounicode(new_feed))</kbd> <span class=u>④</span></a>
|
||||
<samp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'><title type='html'>dive into &amp;hellip;</title></feed></samp>
|
||||
<a><samp class=p>>>> </samp><kbd>print(lxml.etree.tounicode(new_feed, pretty_print=True))</kbd> <span class=u>⑤</span></a>
|
||||
<samp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>title = lxml.etree.SubElement(new_feed, 'title',</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>... </samp><kbd class=pp> attrib={'type':'html'})</kbd> <span class=u>②</span></a>
|
||||
<samp class=p>>>> </samp><kbd class=pp>print(lxml.etree.tounicode(new_feed))</kbd>
|
||||
<samp class=pp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'><title type='html'/></feed></samp>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>title.text = 'dive into &hellip;'</kbd> <span class=u>③</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>print(lxml.etree.tounicode(new_feed))</kbd> <span class=u>④</span></a>
|
||||
<samp class=pp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'><title type='html'>dive into &amp;hellip;</title></feed></samp>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>print(lxml.etree.tounicode(new_feed, pretty_print=True))</kbd> <span class=u>⑤</span></a>
|
||||
<samp class=pp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'>
|
||||
<title type='html'>dive into&amp;hellip;</title>
|
||||
</feed></samp></pre>
|
||||
<ol>
|
||||
@@ -583,8 +583,8 @@ except ImportError:
|
||||
<p>That’s an error, because the <code>&hellip;</code> entity is not defined in <abbr>XML</abbr>. (It is defined in <abbr>HTML</abbr>.) If you try to parse this broken feed with the default settings, <code>lxml</code> will choke on the undefined entity.
|
||||
|
||||
<pre class=screen>
|
||||
<samp class=p>>>> </samp><kbd>import lxml.etree</kbd>
|
||||
<samp class=p>>>> </samp><kbd>tree = lxml.etree.parse('examples/feed-broken.xml')</kbd>
|
||||
<samp class=p>>>> </samp><kbd class=pp>import lxml.etree</kbd>
|
||||
<samp class=p>>>> </samp><kbd class=pp>tree = lxml.etree.parse('examples/feed-broken.xml')</kbd>
|
||||
<samp class=traceback>Traceback (most recent call last):
|
||||
File "<stdin>", line 1, in <module>
|
||||
File "lxml.etree.pyx", line 2693, in lxml.etree.parse (src/lxml/lxml.etree.c:52591)
|
||||
@@ -600,17 +600,17 @@ lxml.etree.XMLSyntaxError: Entity 'hellip' not defined, line 3, column 28</samp>
|
||||
<p>To parse this broken <abbr>XML</abbr> document, despite its wellformedness error, you need to create a custom <abbr>XML</abbr> parser.
|
||||
|
||||
<pre class=screen>
|
||||
<a><samp class=p>>>> </samp><kbd>parser = lxml.etree.XMLParser(recover=True)</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>tree = lxml.etree.parse('examples/feed-broken.xml', parser)</kbd> <span class=u>②</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd>parser.error_log</kbd> <span class=u>③</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>parser = lxml.etree.XMLParser(recover=True)</kbd> <span class=u>①</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>tree = lxml.etree.parse('examples/feed-broken.xml', parser)</kbd> <span class=u>②</span></a>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>parser.error_log</kbd> <span class=u>③</span></a>
|
||||
<samp>examples/feed-broken.xml:3:28:FATAL:PARSER:ERR_UNDECLARED_ENTITY: Entity 'hellip' not defined</samp>
|
||||
<samp class=p>>>> </samp><kbd>tree.findall('{http://www.w3.org/2005/Atom}title')</kbd>
|
||||
<samp>[<Element {http://www.w3.org/2005/Atom}title at ead510>]</samp>
|
||||
<samp class=p>>>> </samp><kbd>title = tree.findall('{http://www.w3.org/2005/Atom}title')[0]</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd>title.text</kbd> <span class=u>④</span></a>
|
||||
<samp>'dive into '</samp>
|
||||
<a><samp class=p>>>> </samp><kbd>print(lxml.etree.tounicode(tree.getroot()))</kbd> <span class=u>⑤</span></a>
|
||||
<samp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'>
|
||||
<samp class=p>>>> </samp><kbd class=pp>tree.findall('{http://www.w3.org/2005/Atom}title')</kbd>
|
||||
<samp class=pp>[<Element {http://www.w3.org/2005/Atom}title at ead510>]</samp>
|
||||
<samp class=p>>>> </samp><kbd class=pp>title = tree.findall('{http://www.w3.org/2005/Atom}title')[0]</kbd>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>title.text</kbd> <span class=u>④</span></a>
|
||||
<samp class=pp>'dive into '</samp>
|
||||
<a><samp class=p>>>> </samp><kbd class=pp>print(lxml.etree.tounicode(tree.getroot()))</kbd> <span class=u>⑤</span></a>
|
||||
<samp class=pp><feed xmlns='http://www.w3.org/2005/Atom' xml:lang='en'>
|
||||
<title>dive into </title>
|
||||
.
|
||||
. [rest of serialization snipped for brevity]
|
||||
|
||||
Reference in New Issue
Block a user