Looping through a hash, or using an array in PowerShell

Christian's answer works well and shows how you can loop through each hash table item using the GetEnumerator method. You can also loop through using the keys property. Here is an example how:

$hash = @{
    a = 1
    b = 2
    c = 3
}
$hash.Keys | % { "key = $_ , value = " + $hash.Item($_) }

Output:

key = c , value = 3
key = a , value = 1
key = b , value = 2

Shorthand is not preferred for scripts; it is less readable. The %{} operator is considered shorthand. Here's how it should be done in a script for readability and reusability:

Variable Setup

PS> $hash = @{
    a = 1
    b = 2
    c = 3
}
PS> $hash

Name                           Value
----                           -----
c                              3
b                              2
a                              1

Option 1: GetEnumerator()

Note: personal preference; syntax is easier to read

The GetEnumerator() method would be done as shown:

foreach ($h in $hash.GetEnumerator()) {
    Write-Host "$($h.Name): $($h.Value)"
}

Output:

c: 3
b: 2
a: 1

Option 2: Keys

The Keys method would be done as shown:

foreach ($h in $hash.Keys) {
    Write-Host "${h}: $($hash.$h)"
}

Output:

c: 3
b: 2
a: 1

Additional information

Be careful sorting your hashtable...

Sort-Object may change it to an array:

PS> $hash.GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Hashtable                                System.Object


PS> $hash = $hash.GetEnumerator() | Sort-Object Name
PS> $hash.GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Object[]                                 System.Array

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This and other PowerShell looping are available on my blog.

You can also do this without a variable

@{
  'foo' = 222
  'bar' = 333
  'baz' = 444
  'qux' = 555
} | % getEnumerator | % {
  $_.key
  $_.value
}