Asp Forum - Pulling text from elements with REXML

Paul Willis

3/19/2007 11:38:00 AM

Hi

I am using REXML to pull text from a NewsML document.

require 'rexml/document'
include REXML
file = File.new("Main_News.xml")
doc = Document.new(file)
root = doc.root
puts
root.elements["NewsItem/NewsComponent/NewsComponent[1]/NewsComponent/ContentItem/DataContent/nitf/body/body.head/hedline/hl1"]

Gives me...

<hl1>Blueprint to cut emissions unveiled</hl1>

Is there an easy way (ie something in REXML) to pull just the text
without the containers <hl1> and </hl1>.

Paul

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9 Answers

Peter Szinek

3/19/2007 11:50:00 AM

Paul Willis wrote:
> Hi
>
> I am using REXML to pull text from a NewsML document.
>
> require 'rexml/document'
> include REXML
> file = File.new("Main_News.xml")
> doc = Document.new(file)
> root = doc.root
> puts
> root.elements["NewsItem/NewsComponent/NewsComponent[1]/NewsComponent/ContentItem/DataContent/nitf/body/body.head/hedline/hl1"]
>
> Gives me...
>
> <hl1>Blueprint to cut emissions unveiled</hl1>
>
> Is there an easy way (ie something in REXML) to pull just the text
> without the containers <hl1> and </hl1>.

If I understood correctly, you need the text content of the node rather
than the whole node. This can be accomplished with:

some_element.text

so you could do something like

root.elements[...your stuff_here...].to_a.each {|e| puts e.text}

HTH,
Peter
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Paul Willis

3/19/2007 12:06:00 PM

Peter Szinek wrote:

> If I understood correctly, you need the text content of the node rather
> than the whole node. This can be accomplished with:
>
> some_element.text
>

You did understand correctly, .text on the end was all I needed.

Cheers

Paul

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Gavin Kistner

3/19/2007 2:04:00 PM

On Mar 19, 5:38 am, Paul Willis <i...@paulwillis.com> wrote:
> root.elements["NewsItem/NewsComponent/NewsComponent[1]/NewsComponent/Conten tItem/DataContent/nitf/body/body.head/hedline/hl1"]
>
> Gives me...
>
> <hl1>Blueprint to cut emissions unveiled</hl1>
>
> Is there an easy way (ie something in REXML) to pull just the text
> without the containers <hl1> and </hl1>.

require 'rexml/document'
doc = REXML::Document.new("<root><kid>hello world</kid></root>")
p REXML::XPath.first( doc, '/root/kid/text()' )
#=> "hello world"

Gavin Kistner

3/19/2007 2:20:00 PM

On Mar 19, 8:04 am, "Phrogz" <g...@refinery.com> wrote:
> On Mar 19, 5:38 am, Paul Willis <i...@paulwillis.com> wrote:
>
> > root.elements["NewsItem/NewsComponent/NewsComponent[1]/NewsComponent/Conten tItem/DataContent/nitf/body/body.head/hedline/hl1"]
>
> > Gives me...
>
> > <hl1>Blueprint to cut emissions unveiled</hl1>
>
> > Is there an easy way (ie something in REXML) to pull just the text
> > without the containers <hl1> and </hl1>.
>
> require 'rexml/document'
> doc = REXML::Document.new("<root><kid>hello world</kid></root>")
> p REXML::XPath.first( doc, '/root/kid/text()' )
> #=> "hello world"

Also, depending on your needs:

include REXML
doc = Document.new("<root><kid>hello</kid><kid>world</kid></root>")
p XPath.match( doc, '/root/kid/text()' )
#=> ["hello", "world"]

Keith Fahlgren

3/19/2007 3:38:00 PM

Hey,

Two notes:
1. I always suggest the REXML::XPath methods over the others for
people who grok XPath.
2. A REXML::XPath.* ... text() match will return a REXML::Text node,
which may _not_ be what you want:

$ irb --simple-prompt foo.rb
>> require 'rexml/document'
=> true
>> doc = REXML::Document.new("<root><kid>hello world</kid></root>")
=> <UNDEFINED> ... </>
>> REXML::XPath.first( doc, '/root/kid/text()' )
=> "hello world"
>> REXML::XPath.first( doc, '/root/kid/text()' ).class
=> REXML::Text

Just something to be aware of (use .to_s if you want a string, as usual).

HTH,
Keith

Paul Willis

3/22/2007 4:45:00 PM

> require 'rexml/document'
> doc = REXML::Document.new("<root><kid>hello world</kid></root>")
> p REXML::XPath.first( doc, '/root/kid/text()' )
> #=> "hello world"

Thanks for that, I'm now using REXML::XPath with a combination of .first
and .match to pull the element text out.

One more thing, given an XML document...

<root><kid stuff="some-other-text">hello world</kid></root>

What would be the path to the attribute 'stuff' and return
'some-other-text'?

Paul

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Gavin Kistner

3/22/2007 4:54:00 PM

On Mar 22, 10:44 am, Paul Willis <i...@paulwillis.com> wrote:
> One more thing, given an XML document...
>
> <root><kid stuff="some-other-text">hello world</kid></root>
>
> What would be the path to the attribute 'stuff' and return
> 'some-other-text'?

require 'rexml/document'
include REXML
doc = Document.new( <<ENDDOC )
<root>
<kid stuff="some-other-text">hello world</kid>
<kid class="best" stuff="gibbles">hello world</kid>
</root>
ENDDOC

att = XPath.first( doc, '//kid/@stuff' )
p att, att.class, att.value
#=> stuff='some-other-text'
#=> REXML::Attribute
#=> "some-other-text"

p XPath.first( doc, '//kid[@class="best"]/@stuff' ).value
#=> "gibbles"

I don't know what the XPath syntax is to select the value of an
attribute directly. I'd be interested to know if someone else knows it.

Paul Willis

3/22/2007 5:03:00 PM

Gavin Kistner wrote:

> att = XPath.first( doc, '//kid/@stuff' )

> I don't know what the XPath syntax is to select the value of an
> attribute directly. I'd be interested to know if someone else knows it.

Cheers, it was the kid/@stuff I needed...

puts XPath.first( doc, '/root/kid/@stuff' )

#=> some-other-text

Paul

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Gavin Kistner

3/22/2007 5:09:00 PM

On Mar 22, 11:02 am, Paul Willis <i...@paulwillis.com> wrote:
> Gavin Kistner wrote:
> > att = XPath.first( doc, '//kid/@stuff' )
> > I don't know what the XPath syntax is to select the value of an
> > attribute directly. I'd be interested to know if someone else knows it.
>
> Cheers, it was the kid/@stuff I needed...
>
> puts XPath.first( doc, '/root/kid/@stuff' )
>
> #=> some-other-text

Nice, I didn't realize that REXML::Attribute had such different output
for #inspect versus #to_s. It's nice, then, that you don't need to
call .value in this particular case. Just be aware that without
the .value call you still have an Attribute instance that can just be
treated as a string in some areas:

att = XPath.first( doc, '//kid/@stuff' )

puts att
#=> some-other-text

puts att.value + '-more'
#=> some-other-text-more

puts att + "-more"
#=> tmp.rb:17: undefined method `+' for
stuff='some-other-text':REXML::Attribute (NoMethodError)

comp.lang.ruby

Pulling text from elements with REXML

Paul Willis

Peter Szinek

Paul Willis

Gavin Kistner

Gavin Kistner

Keith Fahlgren

Paul Willis

Gavin Kistner

Paul Willis

Gavin Kistner

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