Operators-match-notmatch-and-matches

Operators -match, -notmatch do not reset $matches

help about_comparison_operators

    -Match
      Description: Matches a string using regular expressions.
                   When the input is scalar, it populates the
                   $Matches automatic variable.

help about_Automatic_Variables

    $Matches
       The $Matches variable works with the -match and -notmatch operators.
       When you submit scalar input to the -match or -notmatch operator, and
       either one detects a match, they return a Boolean value and populate
       the $Matches automatic variable with a hash table of any string values
       that were matched. For more information about the -match operator, see
       about_comparison_operators.

Help does not explicitly tell what happens to $matches when -match or -notmatch does not detect a match. One may expect that it is reset to empty. But it looks like it is left not changed. In other words, it is populated with some previous results, if any.

Scripts

• Test-1.match.ps1 shows the issue with -match
• Test-2.notmatch.ps1 shows the issue with -notmatch
• Test-3.regex.ps1 shows how [regex] works in this scenario

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• Microsoft Connect 1601710