You probably use it all the time in your scripts, but how do they work? In this blog post, I will show some simple examples of what you can do with them 🙂
What are PowerShell Arrays?
“An array is a data structure that’s designed to store a collection of items. The items can be the same type or different types.
Beginning in Windows PowerShell 3.0, a collection of zero or one object has some properties of arrays”
How do they work?
Basic usage for showing data
If you have a variable in which you store data, it will change to that type. In the example below, I store the results from Get-ChildItem in the variable $array. After storing, I use .Gettype() to show the data type of the variable $array.
As you can see, the Object’s base type is System.Array. When using $array, it will show the output of Get-ChildItem of my Array folder, which contains three TXT files.
To show the number of items in the variable $array, you can use the Count property. For example, using $variable.count will return 3:
If you want only to show the first item of the $array variable, you can use $array[0]. It starts counting at 0, and you can also use $array[1] or $array[2] to display the other items.
You can also show a range of items; in the example below, I only want to show items 1 and 2. You specify the range using double dots like this: $array[1..2]. For example:
Alternatively, you can use the minus sign to retrieve the last items of the $array variable. For example, using $array[-1..-2] will show this:
Looping through an array
With foreach, you can use and act on all the items in the array $array. For example:
Adding items to an Array
You can add more objects to an existing array with the same properties. In the example below, I created a $array2 variable with the contents of the Array2 folder (Also three files):
As you can see, setting $array to be $array plus the newly created $array2 shows that it has 6 items using the Count method and will show File1.txt – File6.txt.
Removing items of an Array
You can remove a specific item from an Array by setting it to $null. For example, below I remove the File6.txt from the Array by using $array[5]=$null:
Clearing the contents of an Array
You can completely remove all the items of an Array by using the Clear method and resetting the $array variable when using $array.Clear():
In the example above, I use $array.Clear() to remove everything, and the type of the variable $array is still System. Array but without contents.
Show all Methods and Properties of an Array
To show all the things you can do or retrieve from the $array variable, you can use Get-Member, as shown in the example below:
As you can see in the picture above, there are many methods and properties that you can use from the $array variable. Using Methods is something I will write about in the future, but accessing properties is simple. For example, using $array.Directory will show all the Directory properties from all items inside the array $array:
But to get that information from a specific item, you can use $array[0].Directory, for example:
Wrapping up
In this blog post, I showed you how an Array works and a few things you can do. For more in-depth details, check out the Microsoft Learn document about it 🙂 Enjoy your weekend!
Very nice Harm. I went through this article this morning while drinking some coffee. Had my terminal side by side going through all these exercises. As always, best PS blogger!
Thank you and coffee is always a good idea 😁