in reply to language selection via libxml

Hi,

$result=$tree->findnodes("/language/$language/widget[@ID="$id"]");

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The @ID is interpreted by Perl as an array access. You have to escape the '@'.

Best regards
McA

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Re^2: language selection via libxml
by tangent (Parson) on Jan 20, 2014 at 12:18 UTC
    Also need to lose the quotes around $id 
    "/language/$language/widget[\@ID=$id]"

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    Update:
    Thanks to choroba's explanations and examples below, this only works by accident, i.e. only if $id is a number.

    Here are some different ways of doing it: 

    "/language/$language/widget[\@ID='$id']"
"/language/$language/widget[attribute::ID='$id']"
qq|/language/$language/widget[\@ID="$id"]|
qq|/language/$language/widget[\@ID='$id']|
qq|/language/$language/widget[attribute::ID="$id"]|
qq|/language/$language/widget[attribute::ID='$id']|

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      Not really. String literals must be enclosed in quotes in XPath expressions, and XPath does not know Perl variables (unless you use XML::XSH2).
      لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]
        With the quotes I get 
        Scalar found where operator expected near ""/language/$language/widget
+[\@ID="$id"

String found where operator expected near "$id"]""

syntax error near ""/language/$language/widget[\@ID="$id"

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        Update: Perhaps I should have said "lose double quotes around $id", though no quotes works for me too: 
        "/language/$language/widget[\@ID="$id"]"  - Error
"/language/$language/widget[\@ID='$id']"  - OK
"/language/$language/widget[\@ID=$id]"    - OK

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