Hi,

Am Dienstag, 30. September 2014, 10:07:47 schrieb Kun JIN:

"nsmap" is an lxml.element function to get namespaces of the element, usually, a None type will be returned, like:

{'olac': 'http://www.language-archives.org/OLAC/1.1/', None: 'http://www.imsglobal.org/xsd/imscp_v1p1%27%7D

i want use this namespaces in XPath, but i got an error: TypeError: empty namespace prefix is not supported in XPath

so, i must delete this NoneType by creating a new dictionay in Python:

dic_ns = {} for element in root.nsmap: if element is None: continue dic_ns[element] = root.nsmap[element]

QUESTION: is there some other methods to do this?

The for loop is too complicated. ;) There is no need to generate a new dictionary. Just delete the key/value with pop():

dic_ns.pop(k[,d]) -> v, remove specified key and return the corresponding value. If key is not found, d is returned if given, otherwise KeyError is raised

To remove any key with None in your dictionary, pass None as the first argument. The second None is used to avoid the KeyError exception, in case there is no key with None:

dic_ns.pop(None, None)