xml实例版本：
<a>
<city:table xmlns:city="city">
<heilongjiang name="citys"><city:haerbin/><city:daqing/></heilongjiang>
<guangdong name="citys"><city:guangzhou/><city:shenzhen/><city:zhuhai/></guangdong>
<taiwan name="citys"><city:taibei/><city:gaoxiong/></taiwan>
<xinjiang name="citys"><city:wulumuqi> 晴</city:wulumuqi></xinjiang>
</city:table>
</a>
<city:table xmlns:city="city"></city:table>
声明命名空间，city为变量，xmlns定义city变量的值。
python 读取输出实例：
xp=xpxlm.xpath('//node()')
print xp, #.items()#.tag
for i in xp:
if '' in i or '\n' in i:
continue
else:
print i.tag输出结果：
{city}table
heilongjiang
{city}haerbin
{city}daqing
guangdong
{city}guangzhou
{city}shenzhen
{city}zhuhai
........改变<city:table xmlns:city="city">为
<city:table xmlns:city="a">
输出结果为：
{a}table
heilongjiang
{a}haerbin
{a}daqing
guangdong
{a}guangzhou
{a}shenzhen
{a}zhuhai
taiwan
{a}taibei
{a}gaoxiong
xinjiang
{a}wulumuqi