Get-Random
Gets a random number, or selects objects randomly from a collection.
Syntax
Get-Random
[-SetSeed <Int32>]
[[-Maximum] <Object>]
[-Minimum <Object>]
[<CommonParameters>]
Get-Random
[-SetSeed <Int32>]
[-InputObject] <Object[]>
[-Count <Int32>]
[<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
).
You can use the parameters of Get-Random
to specify a seed number, minimum and maximum values, and
the number of objects returned from a submitted collection.
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
This command returns the entire collection in random order.
The value of the Count parameter is the MaxValue static property of integers.
To return an entire collection in random order, enter any number that is greater than or equal to the number of objects in the collection.
1, 2, 3, 5, 8, 13 | Get-Random -Count ([int]::MaxValue)
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 is 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, For-EachObject
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
Parameters
-Count
Specifies the number of random objects or numbers to return. The default is 1.
When used with InputObject
, if the value of Count exceeds the number of objects in the
collection, Get-Random
returns all of the objects in random order.
Type: | Int32 |
Position: | Named |
Default value: | None |
Required: | False |
Accept pipeline input: | False |
Accept wildcard characters: | False |
-InputObject
Specifies a collection of objects. Get-Random
gets randomly selected objects in random order from
the collection up to the number specified by Count. Enter the objects, a variable that contains
the objects, or a command or expression that gets the objects. You can also pipe a collection of
objects to Get-Random
.
Type: | Object[] |
Position: | 0 |
Default value: | None |
Required: | True |
Accept pipeline input: | True |
Accept wildcard characters: | False |
-Maximum
Specifies a maximum value for the random number. Get-Random
returns a value that is less than the
maximum (not equal). Enter an integer, a double-precision floating-point number, or an object that
can be converted to an integer or double, such as a numeric string ("100").
The value of Maximum must be greater than (not equal to) the value of Minimum. If the value
of Maximum or Minimum is a floating-point number, Get-Random
returns a randomly selected
floating-point number.
On a 64-bit computer, if the value of Minimum is a 32-bit integer, the default value of Maximum is Int32.MaxValue.
If the value of Minimum is a double (a floating-point number), the default value of Maximum is Double.MaxValue. Otherwise, the default value is Int32.MaxValue.
Type: | Object |
Position: | 0 |
Default value: | None |
Required: | False |
Accept pipeline input: | False |
Accept wildcard characters: | False |
-Minimum
Specifies a minimum value for the random number. Enter an integer, a double-precision floating-point number, or an object that can be converted to an integer or double, such as a numeric string ("100"). The default value is 0 (zero).
The value of Minimum must be less than (not equal to) the value of Maximum. If the value of
Maximum or Minimum is a floating-point number, Get-Random
returns a randomly selected
floating-point number.
Type: | Object |
Position: | Named |
Default value: | None |
Required: | False |
Accept pipeline input: | False |
Accept wildcard characters: | False |
-SetSeed
Specifies a seed value for the random number generator. This seed value is used for the current
command and for all subsequent Get-Random
commands in the current session until you use
SetSeed again or close the session. You cannot reset the seed to its default value.
The SetSeed parameter is not required. By default, Get-Random
uses the
RandomNumberGenerator()
method to generate a seed value. Because SetSeed results in non-random behavior, it is typically
used only when trying to reproduce behavior, such as when debugging or analyzing a script that
includes Get-Random
commands.
Type: | Int32 |
Position: | Named |
Default value: | None |
Required: | False |
Accept pipeline input: | False |
Accept wildcard characters: | False |
Inputs
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
Get-Random
sets a default seed for each session based on the system time clock when the session
starts.
Beginning in Windows PowerShell 3.0, Get-Random
supports 64-bit integers. In Windows PowerShell
2.0, all values are cast to System.Int32.