AttributeError：元素实例没有属性＆＃39; __ float __＆＃39;在Python中

Question

运行脚本时出现此错误

AttributeError: Element instance has no attribute '__float__'

我的代码如下所示：

def populate():
    parsedfiles = minidom.parse('C:\Users\User\Downloads\New folder\StreetTrees_ArbutusRidge.xml')
    treelist = parsedfiles.getElementsByTagName('StreetTree')
    for alltrees in treelist:
        treeId = alltrees.getAttribute('TreeID')
        neighbourhood = alltrees.getElementsByTagName('NeighbourhoodName')
        commonName = alltrees.getElementsByTagName('CommonName')
        diameter = alltrees.getElementsByTagName('Diameter')[0]
        diameter = float(diameter)
        streetNumber = alltrees.getElementsByTagName('CivicNumber')
        street = alltrees.getElementsByTagName('StdStreet')
        lat = 0
        lon = 0
        add_tree(treeId=treeId, neighbourhood=neighbourhood, commonName=commonName,
                 diameter=diameter, streetNumber=streetNumber, street=street, lat=0, lon=0)

我认为我误解了diameter，但我不知道如何解决它。

Answer 1

diameter是一个DOM Element：

diameter = alltrees.getElementsByTagName('Diameter')[0]

它不能直接转换为浮点数，因为那不是文本数据;您可能希望元素中包含的文本：

diameter = alltrees.getElementsByTagName('Diameter')[0]
diameter = float(diameter.firstChild.nodeValue)

请注意，W3C DOM相当麻烦;您可能想要查看更多Pythonic ElementTree API而不是：

parsedfiles = etree.parse(r'C:\Users\User\Downloads\New folder\StreetTrees_ArbutusRidge.xml')
for alltrees in parsedfiles.findall('.//StreetTree'):
    treeId = alltrees. attrib['TreeID']
    neighbourhood = alltrees.findall('NeighbourhoodName')
    commonName = alltrees.findall('CommonName')
    diameter = float(alltrees.find('Diameter').text)
    streetNumber = alltrees.findall('CivicNumber')
    street = alltrees.findall('StdStreet')
    add_tree(treeId=treeId, neighbourhood=neighbourhood, commonName=commonName,
             diameter=diameter, streetNumber=streetNumber, street=street,
             lat=0, lon=0)

我假设您要查找的各种元素直接包含在<StreetTree>元素中。