data3.xml

<data>
    <country name="Liechtenstein">
        <rank>1</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank>4</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
    <country name="Panama">
        <rank>68</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/>
    </country>
</data>

##findall　同じ子ノードすべてを参照する

findやfindallでほしいタグを指定する
以下ではすべてのcountryタグを取得する

from xml.etree import ElementTree


path = 'data3.xml'
tree = ElementTree.parse(path)
root = tree.getroot()
countries = root.findall('country')
for country in countries:
    gdppc = country.find('gdppc')
    print(country.attrib)
    print(gdppc.text)

{'name': 'Liechtenstein'}
141100
{'name': 'Singapore'}
59900
{'name': 'Panama'}
13600

##孫ノードまで取得

for文をネストする。

cnt = 1
for child in root:
    print('---', cnt, '---')
    print(child.tag, child.attrib, child.text)
    for gild in child:
        print(gild.tag, gild.attrib, gild.text)
    cnt += 1

--- 1 ---
country {'name': 'Liechtenstein'}

rank {} 1
year {} 2008
gdppc {} 141100
neighbor {'name': 'Austria', 'direction': 'E'} None
neighbor {'name': 'Switzerland', 'direction': 'W'} None
--- 2 ---
country {'name': 'Singapore'}

rank {} 4
year {} 2011
gdppc {} 59900
neighbor {'name': 'Malaysia', 'direction': 'N'} None
--- 3 ---
country {'name': 'Panama'}

rank {} 68
year {} 2011
gdppc {} 13600
neighbor {'name': 'Costa Rica', 'direction': 'W'} None
neighbor {'name': 'Colombia', 'direction': 'E'} None

##参考URL
https://docs.python.org/ja/3/library/xml.etree.elementtree.html