How to clear multiple local variables in powershell

Note that Lee_Dailey and iRon make sensible recommendations regarding avoiding a large number of variables to begin with:

• Collect multiple values in arrays rather than in individual variables.

• Alternatively, for named access, create multiple values as named (keyed) entries of a single hashtable object or as properties of a single [pscustomobject] instance.

To address the question as asked:

Note that Clear-Variable resets the values of variables to $null, it doesn't actually remove the variables themselves.

To remove variables as a whole, use Remove-Variable.

Both cmdlets:

• accept wildcard patterns as arguments for the -Name parameter; pattern * is the one that matches all names.

  • Important: Do not include $ in the name (pattern); e.g., to remove variable $foo, use Remove-Variable foo.
    (If you mistakenly tried Remove-Variable $foo, the value of variable $foo would be used as the name.)

• have a -Scope parameter that specifies the scope whose variables to target, namely Global, Script, Local, or a numbered scope where 0 is the same as Local, 1 is the parent scope, 2 is the grandparent scope, and so on.

postanote suggests using a shared name prefix, say foo_, for those variables you want to remove all at once, which then allows you to call something like:

Remove-Variable -Scope Local foo_*

Taking a step back: If there's a block of code with variables that you want to restrict to that block, simply use a script block ({ ... }) and invoke it with &, the call operator, which runs the script block in a child scope whose variables go out of scope when execution of the block ends; e.g.:

# Any variables created inside the { ... } block executed 
# with & are scoped to that block.
& {
  foreach ($i in 1..3) {
    $j = $i
  }
}