The array operator, @(), can break up arrays that are used as arguments into operators, or values for parameters.

For example, the format operator, -f, may be used in place of sub-expressions or variable interpolation. @() may be used to define an array to hold the arguments for the operator. The following example shows two different ways of creating the same string:

$item = Get-Item C:Windowsexplorer.exe

# Sub-expressions and variable interpolation
"The file, $($item.Name), with path $item was last written on $($item.LastWriteTime)"

# The format operator
'The file, {0}, with path {1} was last written on {2}' -f @(
    $item.Name
    $item
    $item.LastWriteTime
)

The same approach may be used for replace operations that use particularly long regular expressions. For example, this replace operation attempts to apply a standard format to a UK telephone number. The regular expression benefits from being on a new line:

$ukPhoneNumbers = '+442012345678', '0044(0)1234345678', '+44 (0) 20 81234567', '01234 456789'
$ukPhoneNumbers -replace @(
    '^(?:(?:+|00)d{2})?[ -]*(?:(?0)?[ -]*)?([138]d{1,3}|20)[ -]*(d{3,4})[ -]*(d{3,4})$'
    '+44 $1 $2 $3'
)

@() may also be used with arguments for commands, such as Select-Object:

Get-NetAdapter | Select-Object @(
    'Name'
    'Status'
    'MacAddress'
    LinkSpeed'
    @{ Name = 'IPAddress'; Expression = { ($_ | Get-NetIPAddress).IPAddress }}
)

It is possible to add line breaks into the hashtable that describes the IPAddress property in the preceding example. Doing so may be beneficial if the Expression script grows to be complex.