Powershell RegEx assistance-CodePudding

hoping somebody can help me out here. Current string:

$monthlist = @()
$monthlist = Get-ChildItem $place -Recurse -Directory -force `
| Where-Object { ($_.name -match '((\\0[1-9]|1[0-2])-(200[0-9]|20[1-4][0-9]|205[0-5]))') }

This returns in Powershell:

C:\temp\test\10-2021
C:\temp\test\12-2019
C:\temp\test\2019\12-2019
C:\temp\test\2020\11-2020

But not:

c:\temp\test\08-2021 
c:\temp\test\09-2021

Using https://regex101.com/ and https://regexr.com/ they both say all 6 of the folders listed above should be matching.

I need the \ in the regex string due to there also being several folders such as the following that I do not want to match:

c:\temp\test\01-01-2021
c:\temp\test\05-25-2020

I'm not the best at RegEx and I'm hoping somebody can spot my error pretty quick

CodePudding user response：

The \\ in front of the first group prevents matching against names that start with 0.

If you're worried about matching a substring that's part of a larger string (like 01-2021 in 01-01-2021), make sure you anchor the pattern against the ^ start-of-string and $ end-of-string metacharacters:

... | Where-Object { ($_.name -match '^((0[1-9]|1[0-2])-(200[0-9]|20[1-4][0-9]|205[0-5]))$') }