Skip to main content
C
cleccese1-Visitor
1-Visitor
July 31, 2013
Question

Quick Xpath question

  • July 31, 2013
  • 7 replies
  • 1672 views

<figure><title></title>
<subfig><graphic></graphic><subfig>
<subfig><graphic></graphic><subfig>
<subfig><graphic></graphic><subfig>
</figure>


If I am in subfig #2, and I want to access an attribute (graphsty) of the graphic in subfig #1, would this do? (I am only interested in the graphic immediately preceding the subfig I am in.)


preceding-sibling::subfig[1]/graphic[1][@graphsty] or
preceding-sibling[1]/graphic[1][@graphsty] ?


and if I was in a graphic I would access the previous graphic by


../preceding-sibling::subfig[1]/graphic[1][@graphsty]?

    7 replies

    B
    bibach1-Visitor
    1-Visitor
    July 31, 2013
    Hi, Caroline...

    Your first version should be just about right. The second would not work
    because the name of an axis, such as "preceding-sibling", must always be
    followed by two colons and a node test, such as an element name or wildcard
    (*). Without that, XPath will instead look for elements named
    "preceding-sibling" as children of the current element.

    Keep in mind, also, that expressions in square brackets are just filters,
    rather than steps in the path, so the "[@graphsty]" at the end will just
    discard the "graphic" element if it doesn't have a "graphsty" attribute,
    rather than causing the expression to return the attribute, if present.
    So, you'll probably want "/@graphsty" at the end, instead.

    -Brandon 🙂


    On Tue, Jul 30, 2013 at 11:47 PM, Caroline Leccese <
    caroline@thecodesource.net> wrote:

    > <figure><title></title>
    > <subfig><graphic></graphic><subfig>
    > <subfig><graphic></graphic><subfig>
    > <subfig><graphic></graphic><subfig>
    > </figure>
    >
    > If I am in subfig #2, and I want to access an attribute (graphsty) of the
    > graphic in subfig #1, would this do? (I am only interested in the graphic
    > immediately preceding the subfig I am in.)
    >
    > preceding-sibling::subfig[1]/graphic[1][@graphsty] or
    > preceding-sibling[1]/graphic[1][@graphsty] ?
    >
    > and if I was in a graphic I would access the previous graphic by
    >
    > ../preceding-sibling::subfig[1]/graphic[1][@graphsty]?
    >
    C
    cleccese1-VisitorAuthor
    1-Visitor
    July 31, 2013

    Thanks Brandon!



    So this is what they should be?



    preceding-sibling::subfig[1]/graphic[1][/@graphsty] from <subfig>


    ../preceding-sibling::subfig[1]/graphic[1][/@graphsty] from <graphic>

    C
    cleccese1-VisitorAuthor
    1-Visitor
    July 31, 2013

    From graphic in subfig, I want to check the graphsty att of the graphic in the preceding subfig. I test full-sheet.yn in subfig, but my results are off. The first time the variable should switch from y to n or vice versa there's a delay in my results. Is my logic wrong? If I do ../preceding-sibling::subfig[1]/graphic[1][/@graphsty] I only get 'y' values.


    <graphic in=" subfig="> (graphsty=1 means a half-sheet graphic)


    <att>
    <specval attname="../preceding-sibling::subfig[1]/graphic[1][@graphsty]"&lt;br"/>attloc="#xpath" attval="1"/>
    <charsubset>
    <savetext textid="full-sheet.yn" conrule="\n"/">
    </charsubset>
    </att>


    <att>
    <specval attname="../preceding-sibling::subfig[1]/graphic[1][@graphsty]"&lt;br"/>attloc="#xpath" attval="0"/>
    <charsubset>
    <savetext textid="full-sheet.yn" conrule="\y"/"></charsubset>
    </att>


    test results from <subfig>:
    <graphic>full-sheet=y (correct but irrelevant)


    <graphic>full-sheet=y (correct)


    <graphic graphsty="1">full-sheet=y (correct)


    <graphic graphsty="1">full-sheet=n (incorrect)
    <graphic graphsty="1">full-sheet=n (correct)


    <graphic>full-sheet=n (correct)


    <graphic>full-sheet=n (incorrect)


    <graphic>full-sheet=y (correct)


    <graphic>full-sheet=y (correct)

    C
    cleccese1-VisitorAuthor
    1-Visitor
    July 31, 2013

    Ahh, never mind. preceding-sibling::subfig[1]/graphic[1][@graphsty] works if I set full-sheet.yn in <subfig> instead of <graphic> in <subfig>.

    C
    cleccese1-VisitorAuthor
    1-Visitor
    August 1, 2013

    Arg. If I'm in a following-sibling of figure and I want to get to the preceding graphic, which could be in a subfig or figure, would this do?
    preceding-sibling::*/graphic[1][@graphsty] or


    preceding-sibling::*[1]/graphic[1][@graphsty]


    I don't think that's right.

    G
    GarethOakes16-Pearl
    16-Pearl
    August 1, 2013
    In questions of XPath, I find it always best to break it down to steps:

    preceding-sibling::* = get me a lit of every tag that is at the same level as me, looking "backwards" towards the start of the document (but don't leave our parent tag when looking)
    preceding-sibling::*[1] = get the tag immediately before me (as long as it is still inside our parent tag)

    whatever/graphic[1] = from the list of <graphic> tags under <whatever> get me the first one.

    whatever[@graphsty] = filter the list of <whatever> picking only those which have a graphsty attribute set on them.

    I think what you need in this case is a bit different from your example XPath. Assuming your context is a <figure> and you want the first <graphic> of a <figure> before you (where the <graphic> may be nested in a <subfig>) then you want:
    C
    cleccese1-VisitorAuthor
    1-Visitor
    August 1, 2013

    Thank you, Gareth!

    Terms & ConditionsCookie settingsAccessibility statement