Get-Random

Syntax

Get-Random
   [-SetSeed <Int32>]
   [[-Maximum] <Object>]
   [-Minimum <Object>]
   [-Count <Int32>]
   [<CommonParameters>]

Get-Random
   [-SetSeed <Int32>]
   [-InputObject] <Object[]>
   [-Count <Int32>]
   [<CommonParameters>]

Get-Random
   [-SetSeed <Int32>]
   [-InputObject] <Object[]>
   [-Shuffle]
   [<CommonParameters>]

Description

The Get-Random cmdlet gets a randomly selected number. If you submit a collection of objects to Get-Random, it gets one or more randomly selected objects from the collection.

Without parameters or input, a Get-Random command returns a randomly selected 32-bit unsigned integer between 0 (zero) and Int32.MaxValue (0x7FFFFFFF, 2,147,483,647).

By default, Get-Random generates cryptographically secure randomness using the RandomNumberGenerator class.

You can use the parameters of Get-Random to specify the minimum and maximum values, the number of objects returned from a collection, or a seed number.

Examples

Example 1: Get a random integer

This command gets a random integer between 0 (zero) and Int32.MaxValue.

Get-Random

3951433

Example 2: Get a random integer between 0 and 99

Get-Random -Maximum 100

47

Example 3: Get a random integer between -100 and 99

Get-Random -Minimum -100 -Maximum 100

56

Example 4: Get a random floating-point number

This command gets a random floating-point number greater than or equal to 10.7 and less than 20.92.

Get-Random -Minimum 10.7 -Maximum 20.93

18.08467273887

Example 5: Get a random integer from an array

This command gets a randomly selected number from the specified array.

1, 2, 3, 5, 8, 13 | Get-Random

8

Example 6: Get several random integers from an array

This command gets three randomly selected numbers in random order from an array.

1, 2, 3, 5, 8, 13 | Get-Random -Count 3

3
1
13

Example 7: Randomize an entire collection

Starting in PowerShell 7.1, you can use the Shuffle parameter to return the entire collection in a random order.

1, 2, 3, 5, 8, 13 | Get-Random -Shuffle

2
3
5
1
8
13

Example 8: Get a random non-numeric value

This command returns a random value from a non-numeric collection.

"red", "yellow", "blue" | Get-Random

yellow

Example 9: Use the SetSeed parameter

This example shows the effect of using the SetSeed parameter.

Because SetSeed produces non-random behavior, it's typically used only to reproduce results, such as when debugging or analyzing a script.

# Commands with the default seed are pseudorandom
Get-Random -Maximum 100 -SetSeed 23
Get-Random -Maximum 100
Get-Random -Maximum 100
Get-Random -Maximum 100

74
56
84
46

# Commands with the same seed are not random
Get-Random -Maximum 100 -SetSeed 23
Get-Random -Maximum 100 -SetSeed 23
Get-Random -Maximum 100 -SetSeed 23

74
74
74

# SetSeed results in a repeatable series
Get-Random -Maximum 100 -SetSeed 23
Get-Random -Maximum 100
Get-Random -Maximum 100
Get-Random -Maximum 100

74
56
84
46

Example 10: Get random files

These commands get a randomly selected sample of 50 files from the C: drive of the local computer.

$Files = Get-ChildItem -Path C:\* -Recurse
$Sample = $Files | Get-Random -Count 50

Example 11: Roll fair dice

This example rolls a fair die 1200 times and counts the outcomes. The first command, ForEach-Object repeats the call to Get-Random from the piped in numbers (1-6). The results are grouped by their value with Group-Object and formatted as a table with Select-Object.

1..1200 | ForEach-Object {
    1..6 | Get-Random
} | Group-Object | Select-Object Name,Count

Name Count
---- -----
1      206
2      199
3      196
4      226
5      185
6      188

Example 12: Use the Count parameter

You can now use the Count parameter without piping objects to Get-Random. The following example gets three random numbers less than 10.

Get-Random -Count 3 -Maximum 10

9
0
8

Example 13: Use the InputObject parameter with an empty string or $null

In this example, the InputObject parameter specifies an array that contains an empty string ('') and $null.

Get-Random -InputObject @('a','',$null)

Get-Random will return either a, empty string, or $null. The empty sting displays as a blank line and $null returns to a PowerShell prompt.

Parameters

-Count

-InputObject

-Maximum

-Minimum

-SetSeed

-Shuffle

Inputs

Object

You can pipe one or more objects. Get-Random selects values randomly from the piped objects.

Outputs

System.Int32, System.Int64, System.Double

Get-Random returns an integer or floating-point number, or an object selected randomly from a submitted collection.

Notes

By default, Get-Random generates cryptographically secure randomness using the RandomNumberGenerator class.

Get-Random does not alway return the same data type as the input value. The following table shows the output type for each of the numeric input types.

Input Type	Output Type
SByte	Double
Byte	Double
Int16	Double
UInt16	Double
Int32	Int32
UInt32	Double
Int64	Int64
UInt64	Double
Double	Double
Single	Double

Beginning in Windows PowerShell 3.0, Get-Random supports 64-bit integers. In Windows PowerShell 2.0, all values are cast to System.Int32.

Beginning in PowerShell 7, the InputObject parameter in the RandomListItemParameterSet parameter set accepts arrays that contain an empty string or $null. In earlier PowerShell versions, only the Maximum parameter in the RandomNumberParameterSet parameter set accepted an empty string or $null.

Related Links

• System.Security.Cryptography.RandomNumberGenerator()
• Sytem.Random