元素树寄存器名称

Question

我尝试使用以下项注册命名空间：

ET.register_namespace("inv", "http://www.stormware.cz/schema/version_2/invoice.xsd")

但它不起作用：

Traceback (most recent call last):
  File "C:\tutorial\temp_xml2.py", line 34, in module>
    for listInvoice in root.findall('inv:invoiceHeader'):
  File "C:\Python27\LIB\xml\etree\ElementTree.py", line 390, in findall
    return ElementPath.findall(self, path, namespaces)
  File "C:\Python27\LIB\xml\etree\ElementPath.py", line 293, in findall
    return list(iterfind(elem, path, namespaces))
  File "C:\Python27\LIB\xml\etree\ElementPath.py", line 259, in iterfind
    token = next()
  File "C:\Python27\LIB\xml\etree\ElementPath.py", line 83, in xpath_tokenizer
    raise SyntaxError("prefix %r not found in prefix map" % prefix)
SyntaxError: prefix 'inv' not found in prefix map
>>>

这是怎么回事？

---

谢谢马丁尼

我试过-1.：

for listInvoice in root.findall('inv:invoiceHeader', namespaces=dict(inv='http://www.stormware.cz/schema/version_2/invoice.xsd')):
    invoiceHeader = listInvoice.find('inv:id', namespaces=dict(inv='http://www.stormware.cz/schema/version_2/invoice.xsd')).text
    print invoiceHeader

结果：（空）

2.：

nsmap=root.nsmap
print nsmap

结果：AttributeError:“Element”对象没有属性“nsmap”

3.：

for listInvoice in root.findall('.//{http://www.stormware.cz/schema/version_2/invoice.xsd}invoiceHeader'):
    invoiceHeader = listInvoice.find('.//{http://www.stormware.cz/schema/version_2/invoice.xsd}id').text
    print invoiceHeader

结果：工作正常。

是否有机会立即注册名称空间？然后我想使用listInvoice.find（'inv:id'）.text而不是listInvoice.find（'.//{http://www.stormware.cz/schema/version_2/invoice.xsd}id'）.text（更好的代码和易于阅读）