[MarkLogic Dev General] issue with XPATH

[Geert Josten]

I don't know how Mark Logic implemented the equality operator, but I would think it is O(count(A) * count(B)). Each item from A is compared against each item from B.

But I don't think you need to worry about the order. If you are comparing sequences, you are probably doing that with a purpose.

Kind regards,
Geert

> -----Original Message-----
> From: general-bounces at developer.marklogic.com 
> [mailto:general-bounces at developer.marklogic.com] On Behalf Of 
> Eric Palmitesta
> Sent: donderdag 26 maart 2009 22:58
> To: General Mark Logic Developer Discussion
> Subject: Re: [MarkLogic Dev General] issue with XPATH
> 
> If both sides of the "=" are (unsorted) sequences, then is 
> A=B in O((count(A)+count(B))^2)?
> 
> Eric
> 
> Geert Josten wrote:
> > Pradeep,
> > 
> > Yes, I think the result should be the same. It looks like 
> the first approach is interpreted as (doc(..)//b)[position() = 2].
> > 
> > Eric,
> > 
> > Yes, a = b returns true if any item from sequence a is 
> equal to any item in sequence b. You can best see it as an 
> intersect on atomic values, returning all items in a that are 
> also in b, but none in b that are not in a though..
> > 
> > Kind regards,
> > Geert
> > 
> > 
> > 
> > Drs. G.P.H. Josten
> > Consultant
> > 
> > 
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> > 
> >> From: general-bounces at developer.marklogic.com
> >> [mailto:general-bounces at developer.marklogic.com] On Behalf Of Eric 
> >> Palmitesta
> >> Sent: donderdag 26 maart 2009 21:46
> >> To: General Mark Logic Developer Discussion
> >> Subject: Re: [MarkLogic Dev General] issue with XPATH
> >>
> >> Perhaps I spoke too soon!
> >>
> >> As I understand, A=B means "return true if A is found 
> anywhere in the 
> >> sequence B".  Can someone confirm this?
> >>
> >> Thanks (and sorry to derail),
> >>
> >> Eric
> >>
> >> Eric Palmitesta wrote:
> >>> Equality testing of non-sequences should use "eq".  Try...
> >>>
> >>> [position() eq 2]
> >>>
> >>> Eric
> >>>
> >>> Pradeep Maddireddy wrote:
> >>>> Hi..!
> >>>>
> >>>>
> >>>>
> >>>>   I have a document with the following content
> >>>>
> >>>>
> >>>>
> >>>> <root>
> >>>>
> >>>>   <a>
> >>>>
> >>>>     <b id="1-1">1</b>
> >>>>
> >>>>   </a>
> >>>>
> >>>>   <a>
> >>>>
> >>>>     <b id="2-1">1</b>
> >>>>
> >>>>     <b id="2-2">1</b>
> >>>>
> >>>>   </a>
> >>>>
> >>>>   <a>
> >>>>
> >>>>     <b id="3-1">1</b>
> >>>>
> >>>>     <b id="3-2">1</b>
> >>>>
> >>>>   </a>
> >>>>
> >>>> </root>
> >>>>
> >>>>
> >>>>
> >>>> I think both the following xpath expression should give the same 
> >>>> result but they are giving different results, is it an issue in 
> >>>> marklogic
> >>>>
> >>>>
> >>>>
> >>>> doc("/root/ab.xml")//b[position()=2]
> >>>>
> >>>>
> >>>>
> >>>> <b id="2-1">1</b>
> >>>>
> >>>>
> >>>>
> >>>> doc("/root/ab.xml")//b[2]
> >>>>
> >>>>
> >>>>
> >>>>   <b id="2-2">1</b>
> >>>>   <b id="3-2">1</b>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> Thanks
> >>>>
> >>>> Pradeep Maddireddy
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >> 
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