Question

我有一些问题需要解决python etree库来读取xml文件。我在python中编程很新...所以xml对我来说有点怪......

我在文件中有以下xml结构：

    <sss version="1.2">
    <date>2011-09-23</date>
    <time>12:32:29</time>
    <origin>OPST</origin>
    <user></user>
    <survey>
        <name>Test</name>
        <version>2011-09-02 15:50:10</version>
        <record ident="A">
            <variable ident="10" type="quantity">
                <name>v_682</name>
                <label>Another question</label>
                <position start="23" finish="24"/>
                <values>
                    <range from="0" to="32"/>
                </values>
            </variable>
            <variable ident="11" type="quantity">
                <name>v_683</name>
                <label>another totally another Question</label>
                <position start="25" finish="26"/>
                <values>
                    <range from="0" to="33"/>
                </values>
            </variable>
            <variable ident="12" type="quantity">
                <name>v_684</name>
                <label>And once more Question</label>
                <position start="27" finish="29"/>
                <values>
                    <range from="0" to="122"/>
                </values>
            </variable>
            <variable ident="20" type="single">
                <name>v_685</name>
                <label>Question with alternatives</label>
                <position start="73" finish="73"/>
                <values>
                    <range from="1" to="6"/>
                    <value code="1">Alternative 1</value>
                    <value code="2">Alternative 2</value>
                    <value code="3">Alternative 3</value>
                    <value code="6">Alternative 4</value>
                </values>
            </variable>
        </record>
    </survey>
</sss>

读取元素我开发了一个非常糟糕的循环，这与我猜的etree库的功能不匹配...

from xml.etree.cElementTree import parse
et = parse(open('scheme.xml','rb'))
root = et.getroot()
for i in range(4):
    a= str(root[4][2][i][0].text)
    if a.startswith('v'):
        print root[4][2][i][1].text

如何使用标记结构：例如，读取“value”标记以将文本附加到列表中？

对我来说，这些etree教程非常难以喘息......也许有人可以告诉我如何使用基于标签的搜索...？这些循环太脆弱了...... Thanx很多

Answer 1

如果文件很小而您只需要<value/>个元素：

#!/usr/bin/env python
import xml.etree.cElementTree as etree

tree = etree.parse('scheme.xml')
for value in tree.getiterator(tag='value'):
    print value.get('code'), value.text

如果文件很大：

def getelements(filename, tag):
    context = iter(etree.iterparse(filename, events=('start', 'end')))
    _, root = next(context) # get root element
    for event, elem in context:
        if event == 'end' and elem.tag == tag:
            yield elem
            root.clear() # free memory

for elem in getelements('scheme.xml', 'value'):
    print elem.get('code'), elem.text

输出

1 Alternative 1
2 Alternative 2
3 Alternative 3
6 Alternative 4

要了解详情，请阅读Searching for Subelements和The ElementTree XML API。

需要帮助理解etree xml for python使用标记结构

1 个答案:

输出