PowerShell – hashtable and custom object array about iteration

I often write lists of things and enumerate them to perform some get / set

I hate enumerating hash tables because whenever I have to, I have to bend back to use hash table objects

$hashtablelistofitems = @{}

$hashtablelistofitems.add("i'm a key","i'm a value")

foreach ($item in $hashtablelistofitems.keys) {
  $item
  $hashtablelistofitems.item($item)
}

Instead, I usually revert to a one - dimensional array of custom objects with two noteproperties

$array = @()

$listofitems = "" | select key,value

$listofitems.key = "i'm a key"
$listofitems.value = "i'm a value"

$array += $listofitems

foreach ($item in $listofitems) {
  $item.key
  $item.value
}

Why should I use a hash table on this method? Just because it only guarantees a single value for each key?

Solution

If you want to store a list of key values without creating an array containing a custom object with two properties (key / value), you should use a hash table for two main reasons:

>You may want to pass the hash table to the function that expects the hash table. > Hashtable is a built - in PowerShell type known to all users Your second method is more difficult for other users to read / maintain

Note: you can iterate the hash table by calling the getenumerator() function, which is almost the same as your method:

foreach ($item in $listofitems.GetEnumerator()) {
  $item.key
  $item.value
}

In addition, the hash table comes with convenient methods you may want to use:

@{} | Get-Member | Where-Object MemberType -eq Method | Select Name

Output:

Name             
----             
Add              
Clear            
Clone            
Contains         
ContainsKey      
ContainsValue    
CopyTo           
Equals           
GetEnumerator    
GetHashCode      
GetObjectData    
GetType          
OnDeserialization
Remove           
ToString