powershell xml select attribute value where clause

问题

I have a xml file with the following elements:

<telecom use="HP" value="tel:+1-512-555-1212" />
<telecom use="WP" value="tel:+1-512-123-4567" />

this returns the value of the first node:

$qrda.ClinicalDocument.recordTarget.patientRole.telecom[0].value

However I need to be able to return the node where use="HP" and I'm not certain they'll always be in the correct order.

Any help is much appreciated.

回答1:

The non-XPATH method:

($qrda.ClinicalDocument.recordTarget.patientRole.telecom | Where {$_.use -eq "HP"}).value

Or (thanks to Tomalak's helpful comment), using the comparison statement format:

($qrda.ClinicalDocument.recordTarget.patientRole.telecom | Where use -eq "HP").value

回答2:

Use XPath. Assuming that $qrda is your XML document:

$path = "/ClinicalDocument/recordTarget/patientRole/telecom[@use='HP']"
$telecom = $qrda.SelectSingleNode($path)

since that path is pretty long and overly specific we can trim it down:

$telecom = $qrda.SelectSingleNode("//telecom[@use='HP']")

来源：https://stackoverflow.com/questions/45238987/powershell-xml-select-attribute-value-where-clause