控制搜索深度findall Lxml

Question

I am beginner in Python and trying to Parse XML using LXML in python. I am trying to search a tag using finall() but want to have control of depth where I can search for tag but search doesn't go beyond one level. Explaining below:

<?xml version='1.0' encoding='utf-8'?>
<system xmlns="some_name_space">
<a>
    <host>Random Name</host>
    <class>
        <name>Main_Tag_1</name>
        <detail>
            <name>Child_Tag_1</name>
            <ip>ip_1</ip>
            <port>port_1</port>
        <detail>
    </class>
    <class>
        <name>Main_Tag_2</name>
        <detail>
            <name>Child_Tag_2</name>
            <ip>ip_2</ip>
            <port>port_2</port>
        <detail>
    </class>
    <class>
        <name>Main_Tag_3</name>
        <detail>
            <name>Child_Tag_3</name>
            <ip>ip_3</ip>
            <port>port_3</port>
        <detail>
    </class>
</a>

I am using following python to find for all Main_tags sharing same tag-name as name . I haven't added the complete program here. But this function is a part of class.

def name_ip_dict(self,filename):
self.tag_replace = {}
context = ET.iterparse(filename, tag='{some_name_space}class')
for action,elem in context:
    name_tag = elem.findall(".//{some_name_space}name")
    for name in name_tag: 
        print name.text
        for node in elem:
            ip_list = node.findall(".//{some_name_space}ip") 
            for ip in ip_node_list:
                self.tag_replace.setdefault(name.text, []).append(ip.text)

Right now, I am getting output as

{'Main_Tag_1': ['ip_1'], 'Child_tag_1': ['ip_1'], 'Main_Tag_2': ['ip_2'], 'Child_tag_1': ['ip_2']} and so on..

But I just want to get First Parent ie Main_Tag1,2 or 3 and the text in ip tag.

{'Main_Tag_1': ['ip_1'], 'Main_Tag_2': ['ip_2']} and so on..

This make me feel that there is a need to control depth of findall but I haven't been able to find out anything related to depth on web.

Please let me know if there have already been such use cases and what is the best way to achieve this.

Answer 1

Use single slash ( / ) if you only want to search in direct child elements (not including grand-child and deeper descendant elements) :

name_tag = elem.findall("./{some_name_space}name")

Just a heads up, when you need support for more advanced XPath expressions, use lxml 's xpath() method instead of findall() . The latter only support a very limited set of XPath expressions.