sample_xml='<employees>\
<person id="p1">\
<name value="Alice">ALICE</name>\
</person>\
<person id="p2">\
<name value="Alice">BOB</name>\
</person>\
<person id="p3">\
<name value="Alice"/>\
</person>\
</employees>'
data = [
[f'{sample_xml}']
]
df = spark.createDataFrame(data, ['data'])
df=df.selectExpr(
'xpath(data,"/employees/person/name[#value=\'Alice\']/text()") test'
)
this gives expcted ["ALICE", "BOB"]
Problem:
I want my result to be ["ALICE", "BOB","NA"]
i.e for empty path like below
<name value="Alice"/>
I want to return a default NA .
is it possible to achieve this ?
Regards
With XPath itself this is not possible. It can only return you the actual values of the matching nodes or nothing if no match.
In order to get NA or any other data that is not actually contained in the XML, you should wrap the basic XPath request with some additional, external code to return the customized output in case of no match.
In XPath 2.0, use /employees/person/name[#value=\'Alice\'] /(string(text()), 'NA')[1]".
It can't be done in XPath 1.0. In XPath 1.0 there's no such thing as a sequence of strings; you can only return a sequence of nodes, and you can only return nodes that are actually present in the input document.
Related
I am trying to fetch two nodes from XML as combined result using OR condition.
Nodes in XML where name = John or name="jim",both should be returned . So basically I expect following result:
<person name="John"></person>
<person name="Jim"></person>
I have tried XPath function * ///person[#name="John"] or ///person[#name="Jim"]*
but it gives me only one node.
How to construct Xpath function in this case ?
regards,
Venky
I would use a predicate person[#name = ('John', 'Jim')] if we assume Saxon means a Saxon 9 version where XPath 2 or 3 is supported. Of course the right place for your or expression would be inside the square brackets person[#name = 'Jim' or #name = 'John'].
I have a working multiple node xpath query and I want to add some custom strings between the results.
<FooBar>
<Foo>
<Fooid>A</Fooid>
<Booid>222</Booid>
<Wooid>Z</Wooid>
</Foo>
<Foo>
<Fooid>B</Fooid>
<Booid>333</Booid>
<Wooid>Y</Wooid>
</Foo>
<Foo>
<Fooid>C</Fooid>
<Booid>444</Booid>
<Wooid>X</Wooid>
</Foo>
</FooBar>
I have messed with different combinations of string-joins and/or concats, but the result was always wrong or ended up in a syntax-error. My xpath version is Xpath 2.0
//Foo/Fooid | //Foo/Booid | Foo/Wooid
The above xpath results in:
A
222
Z
My preferred result would be:
(A)
{222}
[Z]
what is the correct usage of string-join in order to get the brackets around the three ids?
after doing some research and with your comments, I was able to achive the desired solution with this line:
//Foo/concat('(', Fooid, ')'), //Foo/concat('{', Booid, '}'),Foo/concat('[', Wooid, ']')
The '|' was replaced by a comma.
to concat these characters, use their html entity instead.
concat('(', //Fooid, ')')
for parentheses use
(
)
for brackets
[
]
for brackes
{
}
See full character entity sets here
I have string xml like below:
<Query>
<Code>USD</Code>
<Description>United States Dollars</Description>
<UpdateTime>2013-03-04 02:27:33</UpdateTime>
<toUSD>1</toUSD>
<USDto>1</USDto>
<toEUR>2</toEUR>
<EURto>3</EURto>
</Query>
All text is in one line without white spaces. I can't write right regex pattern. I want get nodes which begin like <to. For example <toEUR>, <toUSD>.
How should I write this pattern?
With nokogiri and the xpath function starts-with:
require 'nokogiri'
doc = Nokogiri::XML <<EOF
<Query>
<Code>USD</Code>
<Description>United States Dollars</Description>
<UpdateTime>2013-03-04 02:27:33</UpdateTime>
<toUSD>1</toUSD>
<USDto>1</USDto>
<toEUR>2</toEUR>
<EURto>3</EURto>
</Query>
EOF
doc.search('//*[starts-with(name(),"to")]').map &:to_s
#=> ["<toUSD>1</toUSD>", "<toEUR>2</toEUR>"]
Although the general consensus is that parsing xml etc with regex is not the way to go, something like this should do the trick:
<\s*(to[^>\s]+)[^>]*>([^<]+)<\s*/\s*\1\s*>
In ruby format:
/<\s*(to[^>\s]+)[^>]*>([^<]+)<\s*\/\s*\1\s*>/
Matches <toWatever>value</toWhatever> back-reference group 1 returns the name (toWhatever) and back-reference group 2 returns the value.
Basically I need to scrape some text that has nested tags.
Something like this:
<div id='theNode'>
This is an <span style="color:red">example</span> <b>bolded</b> text
</div>
And I want an expression that will produce this:
This is an example bolded text
I have been struggling with this for hour or more with no result.
Any help is appreciated
The string-value of an element node is the concatenation of the string-values of all text node descendants of the element node in document order.
You want to call the XPath string() function on the div element.
string(//div[#id='theNode'])
You can also use the normalize-space function to reduce unwanted whitespace that might appear due to newlines and indenting in the source document. This will remove leading and trailing whitespace and replace sequences of whitespace characters with a single space. When you pass a nodeset to normalize-space(), the nodeset will first be converted to it's string-value. If no arguments are passed to normalize-space it will use the context node.
normalize-space(//div[#id='theNode'])
// if theNode was the context node, you could use this instead
normalize-space()
You might want use a more efficient way of selecting the context node than the example XPath I have been using. eg, the following Javascript example can be run against this page in some browsers.
var el = document.getElementById('question');
var result = document.evaluate('normalize-space()', el, null ).stringValue;
The whitespace only text node between the span and b elements might be a problem.
Use:
string(//div[#id='theNode'])
When this expression is evaluated, the result is the string value of the first (and hopefully only) div element in the document.
As the string value of an element is defined in the XPath Specification as the concatenation in document order of all of its text-node descendants, this is exactly the wanted string.
Because this can include a number of all-white-space text nodes, you may want to eliminate contiguous leading and trailing white-space and replace any such intermediate white-space by a single space character:
Use:
normalize-space(string(//div[#id='theNode']))
XSLT - based verification:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="/">
"<xsl:copy-of select="string(//div[#id='theNode'])"/>"
===========
"<xsl:copy-of select="normalize-space(string(//div[#id='theNode']))"/>"
</xsl:template>
</xsl:stylesheet>
when this transformation is applied on the provided XML document:
<div id='theNode'> This is an
<span style="color:red">example</span>
<b>bolded</b> text
</div>
the two XPath expressions are evaluated and the results of these evaluations are copied to the output:
" This is an
example
bolded text
"
===========
"This is an example bolded text"
If you are using scrapy in python, you can use descendant-or-self::*/text(). Full example:
txt = """<div id='theNode'>
This is an <span style="color:red">example</span> <b>bolded</b> text
</div>"""
selector = scrapy.Selector(text=txt, type="html") # Create HTML doc from HTML text
all_txt = selector.xpath('//div/descendant-or-self::*/text()').getall()
final_txt = ''.join( _ for _ in all_txt).strip()
print(final_txt) # 'This is an example bolded text'
How about this :
/div/text()[1] | /div/span/text() | /div/b/text() | /div/text()[2]
Hmmss I am not sure about the last part though. You might have to play with that.
normal code
//div[#id='theNode']
to get all text but if they become split then
//div[#id='theNode']/text()
Not sure but if you provide me the link I will try
Is there a way to use data from the current context to filter nodes somewhere else in the statsource.
For instance, if I have this XML:
<root>
<group1>
<inst>
<type>Foo</type>
<value>First Foo</value>
</inst>
<inst>
<type>Bar</type>
<value>The Bar</value>
</inst>
<inst>
<type>Foo</type>
<value>Second Foo</value>
</inst>
</group1>
<group2>
<Filter>
<FilterType>Foo</FilterType>
</Filter>
<Filter>
<FilterType>Bar</FilterType>
</Filter>
</group2>
</root>
Assuming my context is one of the Filter tags, I want to return get the number of instances of the specified type in group1. I would like to write XPATH that looks something like this:
count(/root/group1/inst[type = **FilterType**])
Is there anything I can use to get the FilterType in the original context?
This can be done easily in XPath 2.0:
for $type in /*/*/Filter[1]/FilterType
return
count(/*/group1/*[type eq $type])
When this Xpath expression is evaluated against the provided XML document, the correct result is returned:
2
In XPath 1.0, if the number of group1/inst elements is known in advance, and $vType stands for the FilterType in question, then one could construct the following XPath 1.0 expression:
($vType = /*/group1/inst[1]/type)
+
($vType = /*/group1/inst[2]/type)
+
($vType = /*/group1/inst[3]/type)
which again produces:
2.
Finally, if the XPath 1.0 expression is needed in XSLT and the "Filter" is the current node,
then the following XPath expression calculates the exact number of matches:
count(/*/group1/inst[type = curent()/FilterType])
I'm looking for a solution to the same problem. Currently, I'm using a variable to route around this... it'd look something like the following
<xsl:variable name='FilterType'><xsl:value-of select='FilterType'/></xsl:variable>
<xsl:value-of select='count(/root/group1/inst[type = $FilterType])'/>
But there has to be a better way.