Remove PowerShell object properties that match pattern - powershell

Question

Given an example object (coverted from JSON):
{
"Id": 1,
"Name": "Pablo",
"UnwantedProperty1XOXO": true,
"UnwantedProperty2XOXO": false,
"Things": [
{
"Name": "Something",
"UnwantedProperty3XOXO": true
}
]
...
}
How can I remove all properties that match a pattern? In the example I want to remove the three properties that end in XOXO.
My current approach is to use -ExcludeProperty like this:
$myObject | Select-Object -Property * -ExcludeProperty *XOXO
That only removes the first two properties. I need to reach deeper into the collection of Things as well. The object will change as well so I can't hardcode a check for Things and there could be many collections.

Answer 1

Indeed, Select-Object -ExcludeProperty does not act recursively - it only acts on the immediate properties - so a custom solution is needed.
Defining function Remove-Property, printed below, should provide the desired recursive logic:
$sampleJson = #'
{
"Id": 1,
"Name": "Pablo",
"UnwantedProperty1XOXO": true,
"UnwantedProperty2XOXO": false,
"Things": [
{
"Name": "Something",
"UnwantedProperty3XOXO": true
}
]
}
'#
$sampleJson | ConvertFrom-Json |
Remove-Property -NamePattern *XOXO |
ConvertTo-Json
An important aside: ConvertFrom-Json limits parsing to depth of just 2 levels by default, so you may have to specify a greater depth with -Depth <n>.
This problematic default behavior is discussed in GitHub issue #8393.
The result is as follows - note how all properties ending in XOXO, across all levels of the hierarchy, were removed:
{
"Id": 1,
"Name": "Pablo",
"Things": [
{
"Name": "Something"
}
]
}
Remove-Property source code
Important: Remove-Property:
assumes that the input objects are custom objects ([pscustomobject]), such as created by ConvertFrom-Json.
it modifies these objects in place, in addition to outputting the modified object; this differs from Select-Object, which creates new objects from the input.
function Remove-Property {
param(
[Parameter(Mandatory, ValueFromPipeline, Position = 0)]
[object] $InputObject,
[Parameter(Mandatory, Position = 1)]
[string] $NamePattern
)
process {
foreach ($el in $InputObject) {
foreach ($propName in $el.psobject.Properties.Name) {
if ($propName -like $NamePattern) {
$el.psobject.Properties.Remove($propName)
}
else {
$null = Remove-Property -InputObject $el.$propName -NamePattern $NamePattern
}
}
}
$InputObject
}
}

Answer 2

I don't prefer this solution, but it does seem easier than recursively traversing an object's nested properties of unknown depths.
$json = #'
{
"Id": 1,
"Name": "Pablo",
"UnwantedProperty1XOXO": true,
"UnwantedProperty2XOXO": false,
"Things": [
{
"Name": "Something",
"UnwantedProperty3XOXO": true
}
]
}
'#
$filter = "XOXO"
$json -replace ".*$filter.*\r?\n" -replace ",(?=\r?\n\W+})" | ConvertFrom-Json

Answer 3

Maybe this will work.
filter Remove-Property ($Name) {
$queue = [Collections.Generic.Queue[object]]::new(#(Get-Variable _))
while ($queue.Count) {
foreach ($elem in $queue.Dequeue().Value) {
$props = $elem.psobject.Properties
foreach ($p in $props) {
if ($p.Name -like $Name) { $props.Remove($p.Name) } else { $queue.Enqueue($p) }
}
}
}
}
The usage is as follows.
$myObject | Remove-Property -Name "*XOXO"

Answer 4

The ConvertFrom-Json Cmdlet by default has a depth of 2. This is most likely causing your issue.
To fix, use this ConvertFrom-Json command:
ConvertFrom-Json $input -Depth 10
Reference: ConvertFrom-Json