Finding an item in an array

Question

$LogsPath = '\\someserver\somepath\*'
$LogsProperties = Get-ChildItem -Path $LogsPath -recurse |
Select-String -Pattern '[a-z]' |
Select-Object -Property Filename, Path, Line

$Array = @()
$LogsProperties | foreach {
$Array += $LogsProperties
}

The query above will create an array with the following values

(dashes are tabs/columns)

Filename--------------------------Path--------------------------------------------------------------Line

FName1 LName1.txt-----------\\someserver\somepath\FName1 LName1.txt-----------XXX Value
FName2 LName2.txt-----------\\someserver\somepath\FName1 LName1.txt-----------YYY Value
FName3 LName3.txt-----------\\someserver\somepath\FName1 LName1.txt-----------ZZZ Value

$Array[0]

Returns:

FName1 LName1.txt-----------\\someserver\somepath\FName1 LName1.txt-----------XXX Value

Can someone tell me how to search for the index of an element using a value

The function below doesn't work for me

$array.indexof('XXX Value')
0 <-- expected result, index of the array

and will return the error below

Method invocation failed because [System.Object[]] doesn't contain a method named 'indexof'. At line:20 char:15 + $array.indexof <<<< ('XXX Value') + CategoryInfo : InvalidOperation: (indexof:String) [], RuntimeException + FullyQualifiedErrorId : MethodNotFound

score 1 · Answer 1 · answered Sep 08 '18 at 15:21

1

So your $logsProperties is already an array. You can filter using Where-Object or the Where array method:

$logsProperties = Get-ChildItem -Path \\someserver\somepath\* -Recurse |
    Select-String -Pattern '[a-z]' |
    Select-Object -Property FileName, Path, Line

Filtering:

$logsProperties | Where-Object Line -like '*xxx value*'

or:

$logsProperties.Where{$_.Line -like '*xxx value*'}

answered Sep 08 '18 at 15:21

Maximilian Burszley

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This returns the array value not the index of the result :( – Byron Madison Sep 09 '18 at 01:14
@ByronMadison Why do you *need* the index? – Maximilian Burszley Sep 09 '18 at 16:25
I want to call the value of the index, part of a wider plan for the script. I want to get the path and compare it to something else – Byron Madison Sep 09 '18 at 22:26

mklement0 · Accepted Answer · 2022-03-11T00:04:11.887

As pointed out in Maximilian Burszley's answer, $LogsProperties is already an array, whose elements are [pscustomobject] instances with properties FileName, Path, and Line.

(Your attempt to create $Array from $LogsProperties is not only unnecessary, but also broken, because the elements of $Array all end up referencing the array referenced by $LogsProperties as a whole.)

In order to use the .IndexOf() method on array instances^[1], PSv3+ is required. PSv3+ also allows you to use member-access enumeration, so you can apply .IndexOf() to $LogsProperties.Line in order to search the array of .Line property values:

$LogsProperties.Line.IndexOf('XXX Value') # -> 0

In PSv2 you can use a foreach loop to determine the index:

$i = 0
foreach ($obj in $LogsProperties) { if ($obj.Line -eq 'XXX Value') { break }; ++$i }
if ($i -eq $LogsProperties.Count) { $i = -1 }
# $i now contains the index of the matching element or -1, if not found.

^{[1] Type System.Array, the base type for all arrays, also has a static .IndexOf() method that is available in PSv2 too. However, given the need to search the .Line property values of the array elements of $LogProperties, that won't help here, unless a separate array with just the .Line property values is constructed first.}

Utilizing the foreach loop, instead of `break` he could start another variable as such `[string[]]$index += "$i"` to create an array of index's that all contain the search criteria, instead of just the first one. (if that's his goal)... I would also put a `$index = $null` under `$i = 0` — Robert Cotterman, Sep 10 '18 at 04:43
Thanks, @RobertCotterman. Given that the OP tried to use `.IndexOf()`, which only ever returns the _first_ match, I've restricted my `foreach` loop to the same behavior. In the same vein I've just added code to set `$i` to `-1` if no match is found. — mklement0, Sep 10 '18 at 11:23

Finding an item in an array

2 Answers2