以下代码定义并使用 ，该 执行 的 ，并假设其值为非null：
# Function that returns the value of the first property with the given
# name found during recursive depth-first traversal of the given object.
# Note that null-valued properties are ignored.
function Get-FirstPropertyValue($obj, $propName) {
$propNames = $obj.psobject.properties.Name
if ($propName -in $propNames) {
$obj.$propName
} else {
foreach ($iterPropName in $propNames) {
if ($null -ne ($val = Get-FirstPropertyValue $obj.$iterPropName $propName)) {
return $val
}
}
}
}
# Input JSON
$json = @'
{
"nodes": {
"oTUltX4IQMOUUVeiohTt8A": {
"name": "H5dfFeA",
"transport_address": "127.0.0.1:9300",
"host": "127.0.0.1",
"ip": "127.0.0.1:9300",
"tasks": {
"oTUltX4IQMOUUVeiohTt8A:124": {
"node": "oTUltX4IQMOUUVeiohTt8A",
"id": 124,
"type": "direct",
"action": "cluster:monitor/tasks/lists[n]",
"start_time_in_millis": 1458585884904,
"running_time_in_nanos": 47402,
"cancellable": false,
"parent_task_id": "oTUltX4IQMOUUVeiohTt8A:123"
}
}
}
}
}
'@
# Convert the JSON to a [pscustomobject] graph with ConvertFrom-Json.
$objFromJson = $json | ConvertFrom-Json
# Using the function defined above, get the first 'tasks' object found
# during recursive depth-first traversal.
$tasks = Get-FirstPropertyValue $objFromJson 'tasks'
# Get the name of the resulting object's first property.
$propName = @($tasks.psobject.properties.Name)[0]
# Extract the .id property from the object stored in the first property.
$tasks.$propName.id
以上收益：
124
# Input JSON
$json = @'
{
"nodes": {
"oTUltX4IQMOUUVeiohTt8A": {
"name": "H5dfFeA",
"transport_address": "127.0.0.1:9300",
"host": "127.0.0.1",
"ip": "127.0.0.1:9300",
"tasks": {
"oTUltX4IQMOUUVeiohTt8A:124": {
"node": "oTUltX4IQMOUUVeiohTt8A",
"id": 124,
"type": "direct",
"action": "cluster:monitor/tasks/lists[n]",
"start_time_in_millis": 1458585884904,
"running_time_in_nanos": 47402,
"cancellable": false,
"parent_task_id": "oTUltX4IQMOUUVeiohTt8A:123"
}
}
}
}
}
'@
$parent = 'tasks'
$prop = 'id'
$propType = 'int'
$json |
ConvertFrom-Json |
ConvertTo-Xml -Depth ([int]::MaxValue) |
Select-Xml "//Property[@Name='$parent']/*/*[@Name='$prop']/text()" |
ForEach-Object { $_.Node.InnerText -as $propType }
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