Tag Archives: Object

Random Numbers in Powershell

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In one of my last scripts I needed random numbers in Powershell. Now this Blog post should show you how you can generate random numbers in Powershell very simple.

To create random numbers in Powershell you can use the .NET Framework class “System.Random”. First you have to create a new object.

[Object]$Random = New-Object  System.Random

Lets checkout the $Random object:

$Random | Get-Member
   TypeName: System.Random

Name        MemberType Definition
----        ---------- ----------
Equals      Method     bool Equals(System.Object obj)
GetHashCode Method     int GetHashCode()
GetType     Method     type GetType()
Next        Method     int Next(), int Next(int minValue, int maxValue), int Next(int maxValue)
NextBytes   Method     System.Void NextBytes(byte[] buffer)
NextDouble  Method     double NextDouble()
ToString    Method     string ToString()

Now with this object you can now create random numbers very simple:

Create a random double number:

$Random.NextDouble()

Create a random int number:

$Random.Next()

Create a random number between 1 or 10:

$Random.Next(1,11)

Create a random number between 12 or 25:

$Random.Next(12,26)

Create a random number 1 or 0:

$Random.Next(0,2)

Powershell: Working with XML part 2

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After my first post (Powershell: Parsing XML part 1) about working with XML and Powershell, I have create this second post which describes how to create a XML file, Add content to the XML file, remove content from the XML file and save the XML objects as a file.

While I was writing a script which communicates with a webserver, I realized that I need some error handling if the server can not anwser a request from my script. For example if the webserver is down or has to much load.

I created a little retry part (Powershell: Simple retry logic) which retries several times. But if the Server is down for several hours or days your script hangs in a retry loop. Obviously this cant be the solution. After a little bit of thinking a decided to write the data, which I was trying to send, down in a XML file. And the next time the script runs it reads the XML file and tries to send the data again.

Thats the story behind my idea for saving data in a XML file.

Creating a XML object

[XML]$FruitList = "<Box>
<Fruit>
<Name>Banana</Name>
<Color>yellow</Color>
</Fruit>
</Box>"

Save a XML object as a XML file

$FruitList.Save("./myfruitlist.xml")

XML:

<Box>
	<Fruit>
		<Name>Banana</Name>
		<Color>yellow</Color>
	</Fruit>
</Box>

Open a saved XML file

[xml]$FruitList = Get-Content ./myfruitlist.xml

Add data to XML object and save it in a XML file

# Copy Object from Banana
[Object]$CopyFruit = FruitList.Box.Fruit | Where-Object {$_.Name -eq "Banana"}
$NewFruit = $CopyFruit.Clone()
# Add Fruit to new Object
$NewFruit.Name = "Apple"
$NewFruit.Color = "green"
# Add Fruit to XML Object
$FruitList.Box.AppendChild($NewFruit)
#Save to XML object ot XML file
$FruitList.Save("./myfruitlist.xml")

XML:

<Box>
	<Fruit>
		<Name>Banana</Name>
		<Color>yellow</Color>
	</Fruit>
	<Fruit>
		<Name>Apple</Name>
		<Color>green</Color>
	</Fruit>
</Box>

Change data from XML Object and save it as XML file

# Change Apple Color
$FruitList.Box.Fruit | Where-Object {$_.Name -eq "Apple"} | ForEach-Object { $_.Color = "red" }
#Save to XML object ot XML file
$FruitList.Save("./myfruitlist.xml")

XML:

<Box>
	<Fruit>
		<Name>Banana</Name>
		<Color>yellow</Color>
	</Fruit>
	<Fruit>
		<Name>Apple</Name>
		<Color>red</Color>
	</Fruit>
</Box>

Remove data from XML Object and save it as XML file

# Remove Banana from Object
$RemoveFruit = $FruitList.Box.Fruit | Where-Object {$_.Name -eq "Banana"}
$FruitList.Box.RemoveChild($RemoveFruit)
#Save to XML object ot XML file
$FruitList.Save("./myfruitlist.xml")

XML:

<Box>
	<Fruit>
		<Name>Apple</Name>
		<Color>green</Color>
	</Fruit>
</Box>