Python -- xml文件的读取、查询、修改、删除(1)

xml文件的读取、查询、修改、删除

import xml.etree.ElementTree as ET    #因为xml.etree.ElementTree比较长，as用于取个别名

tree = ET.parse("xml_test")
root = tree.getroot()
print(root.tag)

#遍历xml文档
for child in root:
    print(child.tag,child.attrib)
    for i in child:
        print(i.tag,i.text)

#只遍历year节点
for node in root.iter('year'):
    print(node.tag,node.text)

#修改year
for node in root.iter('year'):    #先遍历是否存在‘year’标签
    new_year = int (node.text) + 1    #定义一个变量new_year，赋值为year整形的节点text值+1
    node.text = str(new_year)    #text值再转回字符串格式
    node.set("updated","yes")    #'updated'属性更新为‘yes'
tree.write("xml_test")    #重新写入文档

#删除排名大于50的国家
for country in root.findall('country'):
    rank = int(country.find('rank').text)
    if rank > 50:
        root.remove(country)
tree.write('xml_test1')

被读取的xml_test

<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year updated="no">2011</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated="no">2014</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year updated="no">2014</year>
        <gdppc>13600</gdppc>
        <neighbor direction="W" name="Costa Rica" />
        <neighbor direction="E" name="Colombia" />
    </country>
</data>

被修改后的xml_test

<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year updated="yes">2012</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated="yes">2015</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year updated="yes">2015</year>
        <gdppc>13600</gdppc>
        <neighbor direction="W" name="Costa Rica" />
        <neighbor direction="E" name="Colombia" />
    </country>
</data>

新生成的xml_test1

<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year updated="yes">2012</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated="yes">2015</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
</data>

输出：

data
country {'name': 'Liechtenstein'}
rank 2
year 2011
gdppc 141100
neighbor None
neighbor None
country {'name': 'Singapore'}
rank 5
year 2014
gdppc 59900
neighbor None
country {'name': 'Panama'}
rank 69
year 2014
gdppc 13600
neighbor None
neighbor None
year 2011
year 2014
year 2014