Get index of regex in filename in powershell - regex

Question

I'm trying to get the starting position for a regexmatch in a folder name.
dir c:\test | where {$_.fullname.psiscontainer} | foreach {
$indexx = $_.fullname.Indexofany("[Ss]+[0-9]+[0-9]+[Ee]+[0-9]+[0-9]")
$thingsbeforeregexmatch.substring(0,$indexx)
}
Ideally, this should work but since indexofany doesn't handle regex like that I'm stuck.

Answer 1

You can use the Regex.Match() method to perform a regex match. It'll return a MatchInfo object that has an Index property you can use:
Get-ChildItem c:\test | Where-Object {$_.PSIsContainer} | ForEach-Object {
# Test if folder's Name matches pattern
$match = [regex]::Match($_.Name, '[Ss]+[0-9]+[0-9]+[Ee]+[0-9]+[0-9]')
if($match.Success)
{
# Grab Index from the [regex]::Match() result
$Index = $Match.Index
# Substring using the index we obtained above
$ThingsBeforeMatch = $_.Name.Substring(0, $Index)
Write-Host $ThingsBeforeMatch
}
}
Alternatively, use the -match operator and the $Matches variable to grab the matched string and use that as an argument to IndexOf() (using RedLaser's sweet regex optimization):
if($_.Name -match 's+\d{2,}e+\d{2,}')
{
$Index = $_.Name.IndexOf($Matches[0])
$ThingsBeforeMatch = $_.Name.Substring(0,$Index)
}

Answer 2

You can use the Index property of the Match object. Example:
# Used regEx fom #RedLaser's comment
$regEx = [regex]'(?i)[s]+\d{2}[e]+\d{2}'
$testString = 'abcS00E00b'
$match = $regEx.Match($testString)
if ($match.Success)
{
$startingIndex = $match.Index
Write-Host "Match. Start index = $startingIndex"
}
else
{
Write-Host 'No match found'
}