xpath: nested nodes with same name - xpath

Is it possible to write Xpath exression to find following nodes:
a/b/c
a/b/b/c
a/b/b/b/c
a/b/b/b/.../b/.../b/c
etc.
but not
a/b/b/e/b/c
?
Thanks for any advice

For the following input:
<root>
<a><b><c>1</c></b></a>
<a><b><b><c>2</c></b></b></a>
<a><b><b><b><c>3</c></b></b></b></a>
<a><b><b><e><b><c>4</c></b></e></b></b></a>
<a><b><b><e><b><b><c>5</c></b></b></e></b></b></a>
</root>
You can try the following expression:
//a[deep-equal(distinct-values(descendant::*[position()<last()]/name()), ('b'))]//c
How it works:
For any a the names of all but the last descendant are calculated and it is checked if the distinct list of that names matches the list containing just b. And for such an a the descendant c is one you want to select.
I tested it with the 2010 version of XMLSpy, which returns the c elements containing 1, 2 and 3. I think more modern tools will also work. But you need at least XPath 2.0 for this.

Question is not totally clear, but you can try to use below expression:
//a[.//b and not(.//e)]//c[not(.//*)]
This should allow to match cthat has no own child and is descendant of a, that has b descendant, but not e
UPDATE
You can try
//a[count(.//b)=count(.//*)-count(.//c)]//c[not(.//*)]
or
//a[not(.//*[not(self::b)]//c)]//c[not(.//*)]

Related

Select XML Node by position

I have the following XML structure
<Root>
<BundleItem>
<Item>1</Item>
<Item>2</Item>
<Item>3</Item>
</BundleItem>
<Item>4</Item>
<Item>5</Item>
<Item>6</Item>
<BundleItem>
<Item>7</Item>
<Item>8</Item>
<Item>9</Item>
</BundleItem>
</Root>
And by providing the following xPath
//Item[1]
I am selecting
<Item>1</Item>
<Item>4</Item>
<Item>7</Item>
My goal is to select only <Item>1</Item> or <Item>7</Item> regardless of the parent element where they are found and only depending on the position, which i am providing in the xPath.
Is it possible to do that only by using the position and without providing additional criterias in the xPath ?
//Item[1] selects the all the first child elements that are <Item/> regardless of their parent.
To get the two items you are looking for you could use //Item[text() = 1 or text() = 7].
A good tutorial can be found at w3schools.com and you can play with XPath expressions over your XML input here. (I am not affiliated with either of these resources but find them useful.)

Using XPATH previous:: more like an array

I've got XML like this
<root>
...
<a>
<a>
<a>
<c>
...
It's very flat with LOTS of A elements and a few C elements. The A elements are sensor data and the last reading is bogus, I need the one before. So I'd like to use the C elements as a marker and each of A elements 2 before each C. So I'm trying out an XPATH like:
/root/c/preceding-sibling::a
but I'm getting all previous A elements, I was hoping for something a bit more direct such as:
/root/c/preceeding-sibling[-2]
which would just grab the 2nd sibling before C (no matter the type) I guess I'm asking for array like functionality on an XPATH so what ever I match I can ask for "the second element before that"
Is this possible?
You can
just grab the 2nd sibling before C (no matter the type)
with the XPath expression
/root/c/preceding-sibling::*[2]
The node count for preceding-sibling:: is going backwards. The node with the index [1] is the node before c and the node with the index [2] is the node before this - which is
the second element before that

Xpath Multiple Predicates

I am trying to quickly find a specific node using XPath but it seems my multiple predicates are not working. The div I need has a specific class, but there are 3 others that have it. I want to select the fourth one so I did the following:
//div[#class='myCLass' and 4]
However the "4" is being ignored. Any help? I am new to XPath.
Thanks.
If a xpath query returns a node set you can always use the [OFFSET] operator to access a certain element of it.
Use the following query to access the fourth element that matches the #class='myClass' predicate:
//div[#class='myCLass'][4]
#WilliamNarmontas answer might be an alternative to the syntax showed above.
Alternatively,
//div[#class='myCLass' and position()=4]
The accepted answer works correctly only if all of the div elements have the same parent. Otherwise use:
(//div[#class='myCLass'])[4]

Find attribute names that start with a certain pattern

I am looking to find all attributes of an element that match a certain pattern.
So for an element
<element s2="1" name="aaaa" id="1" />
<element s3="1" name="aaaa" id="2" />
I would like to be able to find all attributes that start with 's' (returning the value of s1 for the first element and s3 for the value of the second element).
If this is outside of xpath's ability please let me know.
Use:
element/#*[starts-with(name(), 's')]
This XPath expression selects all atribute nodes whose name starts with the string 's' and that are attributes of elements named element that are children of the current node.
starts-with() is a standard function in XPath 1.0
element/#*[substring(name(), 1,1) = "s"]
will match any attribute that starts with 's'.
The function starts-with() might look better than using substring()
I've tested the given answers from both #Dimitre-Novatchev and #Ledhund, using lxml.html module in Python.
Both element/#*[starts-with(name(), 's')] and element/#*[substring(name(), 1,1) = "s"] return only the values of s2 and s3. You won't be able to know which value belong to which attribute.
I think in practice I would be more interested in finding the elements themselves that contain the attributes of names starting with specific characters rather than just their values.
To achieve that is very simple, just add /.. at the end,
element/#*[starts-with(name(), "s")]/..
or
element/#*[starts-with(name(), "s")]/parent::*
or
element/#*[starts-with(name(), "s")]/parent::node()
None from above worked for me.
So I did not some changes and it worked for me. :)
/*:UserCustomField[starts-with(#name, 'purchaseDate')]

Can't get nth node in Selenium

I try to write xpath expressions so that my tests won't be broken by small design changes. So instead of the expressions that Selenium IDE generates, I write my own.
Here's an issue:
//input[#name='question'][7]
This expression doesn't work at all. Input nodes named 'question' are spread across the page. They're not siblings.
I've tried using intermediate expression, but it also fails.
(//input[#name='question'])[2]
error = Error: Element (//input[#name='question'])[2] not found
That's why I suppose Seleniun has a wrong implementation of XPath.
According to XPath docs, the position predicate must filter by the position in the nodeset, so it must find the seventh input with the name 'question'. In Selenium this doesn't work. CSS selectors (:nth-of-kind) neither.
I had to write an expression that filters their common parents:
//*[contains(#class, 'question_section')][7]//input[#name='question']
Is this a Selenium specific issue, or I'm reading the specs wrong way? What can I do to make a shorter expression?
Here's an issue:
//input[#name='question'][7]
This expression doesn't work at all.
This is a FAQ.
[] has a higher priority than //.
The above expression selects every input element with #name = 'question', which is the 7th child of its parent -- and aparently the parents of input elements in the document that is not shown don't have so many input children.
Use (note the brackets):
(//input[#name='question'])[7]
This selects the 7th element input in the document that satisfies the conditions in the predicate.
Edit:
People, who know Selenium (Dave Hunt) suggest that the above expression is written in Selenium as:
xpath=(//input[#name='question'])[7]
If you want the 7th input with name attribute with a value of question in the source then try the following:
/descendant::input[#name='question'][7]

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