图片说明 

import xml.etree.ElementTree as ET
# 使用minidom解析器打开 XML 文档
tree = ET.parse("train.xml")     #打开xml文档 

root = tree.getroot()

dictlabel = {'negative':'-1','positive':'1','neutral':'0'}

for sentence in root.findall('sentence'): #找到root节点下的所有country节点 
    text = sentence.find('text').text   #子节点下节点rank的值 
    aspectTerms = sentence.find('aspectTerms')
    for aspectTerm in aspectTerms:

        term = aspectTerm.get('term')      #子节点下属性name的值 
        polarity = aspectTerm.get('polarity')