Like IF, but different

Please ensure you have a solid understanding of IF Statements before continuing with this article.

Let’s say you have some condition to evaluate and depending on its value you might have a whole heap of different actions. For example let’s say your condition can output 1,2,3,4,5 and depending on each number you want to do something different. We could do this with elseif {} statements.

This can get pretty long and difficult to work with if you have loads of different options, and becomes fairly painful to maintain.

For this sort of function we have the switchstatement.

switch(Expression) {
	Result1 { Do-something}
	Result2 { Do-somethingElse}
}

It evaluates anything inside its () brackets, and then carries out some corresponding action. Here is an example of a switch statement:

$value = 4

switch ($value) {
	2 { 'We have a 1'}
	4 { 'We have a 4'}
	6 { 'We have a 6'}
}

More than 1 input

Switches are great for evaluating multiple input values, a switch will sequentially run the inputs through left to right.

switch (5,1,3) {
	1 { 'itsa 1'}
	2 { 'itsa 2'}
	3 { 'itsa 3'}
	4 { 'itsa 4'}
	5 { 'itsa 5'}
}

Break

Just like with For Each Looping we can stop the checks early.

switch (5,1,3) {
	1 { 'itsa 1'}
	2 { 'itsa 2'}
	3 { 'itsa 3'}
	4 { 'itsa 4'}
	5 { 'itsa 5'; Break}
}

We only get the first result because we’ve instructed the switch statement to stop with break.

Default

If we want something to happen when the value doesn’t match anything, we can have a default block:

switch ("this") {
	1 {"It is one"}
	2 {"It is two"}
	"three" {"It is three"}
	Default {
		"What is this?"
	}
}

Wildcard

In the case you need a partial match you can use switch with a -wildcard:

switch -wildcard ("119-281-299-919") {
	1 { "1" }
	2 { "2" } 
	"*299*" { "bingo"}
}

Regex

Similarly Regex can be used instead:

switch -regex ("1234-12-123-1234") {
	"^\w$" {"letter"}
	"^\d%" {"digit"}
	"^\d{3}-$" {"three digits followed by a -"}
	"^\d{4}-\d{2}-\d{3}-\d{4}" {"magic"}
	 
}

Using Script Blocks as Conditions

switch (4) {
	{$_ -is [String]} {
		"Found a String"
	}
	{$_ -is [Int32]} {
		"Found a Number"
	}
}

If the above is not making a ton of sense, refer to the below: $_ Variable