14

Anyone know how I can have a switch statement with multiple possible values like the example below?

switch ($myNumber) {
   1 3 5 7 9 { write-host "Odd" }
   2 4 6 8 10 {write-host "Even" }
}

Used to be easy in VBScript, so I'm sure I'm just missing something simple.

e.g in VBScript

Select Case myNumber 
   Case 1,3,5,7,9
      MsgBox "Odd"
   Case 2,4,6,8,10
      MsgBox "Even"
End Select

5 Answers 5

13
$myNumber = 3
$arrA = 1, 3, 5, 7, 9
$arrB = 2, 4, 6, 8, 10
switch ($myNumber) { 
    {$arrA -contains $_} { write-host "Odd" } 
    {$arrB -contains $_} { write-host "Even" }
}
0
12

In your case you can simply use

switch ($myNumber) {
  { $_ % 2 -eq 1 } { "Odd" }
  { $_ % 2 -eq 0 } { "Even" }
}

An actual attempt to model what you can do there in VB would probably be something like

switch ($myNumber) {
  { 1,3,5,7,9  -contains $_ } { "Odd" }
  { 2,4,6,8,10 -contains $_ } { "Even" }
}
1
  • I like this one better because it's more familiar to traditional switch statements. Apr 13, 2012 at 8:49
2

switch ($myNumber) {
{$_ -in 1, 3, 5, 7, 9} { write-host "Odd" }
{$_ -in 2, 4, 6, 8, 10} {write-host "Even" }
}

1

Adding this for completeness...

The closest PowerShell code to the above VB script is:

PS C:\> switch (1) {  
  {$_ -eq 1 -or $_ -eq 3 -or $_ -eq 5 -or $_ -eq 7 -or $_ -eq 9} { "Odd"}
  {$_ -eq 2 -or $_ -eq 4 -or $_ -eq 6 -or $_ -eq 8 -or $_ -eq 10} { "Even"}
}
Odd

PS C:\VSProjects\Virtus\App_VM> switch (2) {  
  {$_ -eq 1 -or $_ -eq 3 -or $_ -eq 5 -or $_ -eq 7 -or $_ -eq 9} { "Odd"}
  {$_ -eq 2 -or $_ -eq 4 -or $_ -eq 6 -or $_ -eq 8 -or $_ -eq 10} { "Even"}
}
Even

Because the VB script Select Case operates via an OR

Select Case testexpression
   [Case expressionlist-n
      [statements-n]] . . .
   [Case Else
      [elsestatements-n]]
End Select

"If testexpression matches any Case expressionlist expression, the statements following that Case clause are executed up to the next Case clause..." Select Case Statement

The interesting thing that I have not been able to figure out is this result:

PS C:\> switch (1) {  
  {1 -or 3 -or 5 -or 7 -or 9} { "Odd"}
  {2 -or 4 -or 6 -or 8 -or 10} { "Even"}
}
Odd
Even 
-1

How about this for an easy alternative using regex?

switch -regex ($myNumber)
{
   "^[13579]$"     { Write-Host "Odd" }
   "^([2468]|10)$" { Write-Host "Even" }
   default         { Write-Host "Other" }
}
0

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