Some of the operators that work on variables also work on arrays. Let’s start with addition.

Adding Arrays

The addition operator + concatenates – or combines – two arrays.

PS > $fibonacci = 0, 1, 1, 2, 3, 5
PS > $fib_2 = 8, 13, 21, 34
PS > $fibonacci + $fib_2
0
1
1
2
3
5
8
13
21
34

Multiplying Arrays

The multiplication operator * copies the array a specified number of times.

PS > $fib_2 * 2
8
13
21
34
8
13
21
34

We could also use the addition += or multiplication *= assignment operators to assign the resulting array back to the main array.

Containment Operators

Containment operators check whether or not an item is in an array and returns a boolean. There are four operators:

• -contains: <array> -contains <item>
• -notcontains: <array> -notcontains <item>
• -in: <item> -in <array>
• -notin: <item> -notin <array>

Let’s look at a few examples:

PS > $fibonacci -contains 4
False
PS > 5 -in $fibonacci
True

The -contains and -in operators do not differ in functionality, only the order of the operands.

-join

The -join operator combines the items in an array into a string separated by a character or a string. Consider the following example:

PS > $fibonacci = 0, 1, 1, 2, 3, 5
PS > $fibonacci = $fibonacci -join "->"
PS > $fibonacci
0->1->1->2->3->5
PS > $fibonacci.GetType().Name
String

Strongly Typed Arrays

Similar to how we can force a type on a variable to create constrained variables. We can force a type onto an array so that each item has to adhere to that type. For example, if we wanted to force an array only to have strings, we can use the following notation:

PS > [String[]]$fruits = "apple", "banana", "kiwi"

Arrays of Objects

Arrays can hold objects too! Consider the following array:

$dogs_arr = @(
    [PSCustomObject]@{Name = 'Rufus'; Age = 10}
    [PSCustomObject]@{Name = 'Miku'; Age = 2}
)

We utilize the multiline format of creating an array and hashtables to populate the array with dog objects. We can then access objects individually, including their properties and methods.

PS > $dogs_arr.ForEach({ $_.Name + " is " + $_.Age + " years old."})
Rufus is 10 years old.
Miku is 2 years old.