XPATH to select parent node along with child node

Question

I have below xml file wherein I want to select hostname,instance name, instance type using XPATH

<root>
<hosts>
    <host id="11">
        <name>ABC</name>
        <instances>
            <instance id="11-1">
                <name>raj</name>
                <type>linux</type>
                <date>2017</date>
            </instance>
            <instance id="11-2">
                <name>raj1</name>
                <type>linux</type>
                <date>2017</date>
            </instance>
        </instances>
    </host>
    <host id="12">
        <name>XYZ</name>
        <instances>
            <instance id="12-1">
                <name>rahul</name>
                <type>solaris</type>
                <date>2017</date>
            </instance>
        </instances>
    </host>
</hosts>
</root>

I have tried below XPATH which is selecting instance name and type but not sure how to print host name along with instance name and type.

//hosts/host/instances/instance/*[self::name or self:: type]/text()

It selects the below result.

    raj
    linux
    raj1
    linux
    rahul
    solaris

However, I want output like below which has host name included

    ABC
    raj
    linux
    raj1
    linux
    XYZ
    rahul
    solaris

FYI, // is quite expensive here -- it tells your XPath engine it needs to search for hosts elements anywhere in the tree, instead of only directly under root. In some engines there's an index for that kind of lookup (BaseX comes to mind), but that's by no means a universal feature. — Charles Duffy
– Charles Duffy, Commented Jun 30, 2017 at 11:06
(so if efficiency is important to you, consider /root/hosts instead of //hosts). — Charles Duffy
– Charles Duffy, Commented Jun 30, 2017 at 11:16

Charles Duffy · Accepted Answer · 2017-06-30 11:13:29Z

2

The following (using the | operator to combine the sets of elements selected by any of three queries) will do:

  //hosts/host[./instances/instance/name or ./instances/instance/type]/name/text()
| //hosts/host/instances/instance/name/text()
| //hosts/host/instances/instance/type/text()

answered Jun 30, 2017 at 11:13

Charles Duffy

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Andersson · Accepted Answer · 2017-06-30 11:13:13Z

1

If you want to include output for hostname also, try below:

//hosts/host//*[self::name or self:: type]/text()

answered Jun 30, 2017 at 11:13

Andersson

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3 Comments

Charles Duffy Over a year ago

Hmm. This probably does do what the OP wants, but doesn't do what they specify (which, if read literally, indicates that only the names which are under a host which has either an name or type attached to an instance should be included).

Andersson Over a year ago

Yep, this could return wrong output in case of type node under host... Otherwise this should be an acceptable solution

Charles Duffy Over a year ago

I was more concerned with whether the name of a host with no instances should be included -- the way I read the OP they're implying that it shouldn't, though that could well be an unintended consequence of the way they chose to pose the question.

Pradeep Prasad · Accepted Answer · 2017-06-30 16:01:45Z

1

You can achieve your desired result by using any one of below solution -

Solution - 1(Full Path) - you can skip root:

/root/hosts/host/name[text()]|/root/hosts/host/instances/instance/*[self::name or self::type]

Solution - 2(Full Path) with separate query for each result:

/root/hosts/host/name[text()] |/root/hosts/host/instances/instance/name[text()]|/root/hosts/host/instances/instance/type[text()]

Solution - 3(Node Path)

//host/name[text()]|//instance/*[self::name | self::type]

Solution - 4(Node Path)

//host/[self::name]|//instance/[self::name | self::type]

Hope above is helpful.

edited Jun 30, 2017 at 16:01

answered Jun 30, 2017 at 15:54

Pradeep Prasad

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XPATH to select parent node along with child node

3 Answers 3

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3 Comments

Solution - 1(Full Path) - you can skip root:

Solution - 2(Full Path) with separate query for each result:

Solution - 3(Node Path)

Solution - 4(Node Path)

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3 Answers 3

Comments

3 Comments

Solution - 1(Full Path) - you can skip root:

Solution - 2(Full Path) with separate query for each result:

Solution - 3(Node Path)

Solution - 4(Node Path)

Comments

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