admin/PowerShell-PowerShell
1
0
Fork 0
mirror of https://github.com/PowerShell/PowerShell synced 2026-06-08 12:12:50 +00:00
Code Issues Packages Projects Releases Wiki Activity

Refactor Shuffle in Get-Random to save a full iteration of the objects. (#8969)

Browse Source
This commit is contained in:
Gaurav Kamath
2019-03-01 17:11:37 +05:00
committed by Ilya
parent 6f6b7983b0
commit f31b33863c
2 changed files with 49 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/Microsoft.PowerShell.Commands.Utility/commands/utility/GetRandomCommand.cs
+5 -11
View File
@@ -520,23 +520,17 @@ namespace Microsoft.PowerShell.Commands
int n = _chosenListItems.Count;
for (int i = 0; i < n; i++)
{
// randomly choose an item to go into the i-th position
// randomly choose j from [i...n)
int j = this.Generator.Next(i, n);
// swap j-th item into i-th position
this.WriteObject(_chosenListItems[j]);
// remove the output object from consideration in the next iteration.
if (i != j)
{
object tmp = _chosenListItems[i];
_chosenListItems[i] = _chosenListItems[j];
_chosenListItems[j] = tmp;
_chosenListItems[j] = _chosenListItems[i];
}
}
// output all items
foreach (object chosenItem in _chosenListItems)
{
this.WriteObject(chosenItem);
}
}
}
test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Random.Tests.ps1
+44 -42
View File
@@ -85,84 +85,86 @@ Describe "Get-Random DRT Unit Tests" -Tags "CI" {
Describe "Get-Random" -Tags "CI" {
It "Should return a random number greater than -1 " {
Get-Random | Should -BeGreaterThan -1
Get-Random | Should -BeGreaterThan -1
}
It "Should return a random number less than 100 " {
Get-Random -Maximum 100 | Should -BeLessThan 100
Get-Random -Maximum 100 | Should -BeGreaterThan -1
Get-Random -Maximum 100 | Should -BeLessThan 100
Get-Random -Maximum 100 | Should -BeGreaterThan -1
}
It "Should return a random number less than 100 and greater than -100 " {
$randomNumber = Get-Random -Minimum -100 -Maximum 100
$randomNumber | Should -BeLessThan 100
$randomNumber | Should -BeGreaterThan -101
$randomNumber = Get-Random -Minimum -100 -Maximum 100
$randomNumber | Should -BeLessThan 100
$randomNumber | Should -BeGreaterThan -101
}
It "Should return a random number less than 20.93 and greater than 10.7 " {
$randomNumber = Get-Random -Minimum 10.7 -Maximum 20.93
$randomNumber | Should -BeLessThan 20.93
$randomNumber | Should -BeGreaterThan 10.7
$randomNumber = Get-Random -Minimum 10.7 -Maximum 20.93
$randomNumber | Should -BeLessThan 20.93
$randomNumber | Should -BeGreaterThan 10.7
}
It "Should return same number for both Get-Random when switch SetSeed is used " {
$firstRandomNumber = Get-Random -Maximum 100 -SetSeed 23
$secondRandomNumber = Get-Random -Maximum 100 -SetSeed 23
$firstRandomNumber | Should -Be $secondRandomNumber
$firstRandomNumber = Get-Random -Maximum 100 -SetSeed 23
$secondRandomNumber = Get-Random -Maximum 100 -SetSeed 23
$firstRandomNumber | Should -Be $secondRandomNumber
}
It "Should return a number from 1,2,3,5,8,13 " {
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13
$randomNumber | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13
$randomNumber | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
}
It "Should return an array " {
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Count 3
$randomNumber.Count | Should -Be 3
,$randomNumber | Should -BeOfType "System.Array"
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Count 3
$randomNumber.Count | Should -Be 3
,$randomNumber | Should -BeOfType "System.Array"
}
It "Should return three random numbers for array of 1,2,3,5,8,13 " {
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Count 3
$randomNumber[0] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[1] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[2] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[3] | Should -BeNullOrEmpty
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Count 3
$randomNumber.Count | Should -Be 3
$randomNumber[0] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[1] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[2] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[3] | Should -BeNullOrEmpty
}
It "Should return all the numbers for array of 1,2,3,5,8,13 in no particular order" {
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Count ([int]::MaxValue)
$randomNumber[0] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[1] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[2] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[3] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[4] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[5] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[6] | Should -BeNullOrEmpty
$randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Count ([int]::MaxValue)
$randomNumber.Count | Should -Be 6
$randomNumber[0] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[1] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[2] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[3] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[4] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[5] | Should -Be (1 -or 2 -or 3 -or 5 -or 8 -or 13)
$randomNumber[6] | Should -BeNullOrEmpty
}
It "Should return for a string collection " {
$randomNumber = Get-Random -InputObject "red", "yellow", "blue"
$randomNumber | Should -Be ("red" -or "yellow" -or "blue")
$randomNumber = Get-Random -InputObject "red", "yellow", "blue"
$randomNumber | Should -Be ("red" -or "yellow" -or "blue")
}
It "Should return a number for hexadecimal " {
$randomNumber = Get-Random 0x07FFFFFFFFF
$randomNumber | Should -BeLessThan 549755813887
$randomNumber | Should -BeGreaterThan 0
$randomNumber = Get-Random 0x07FFFFFFFFF
$randomNumber | Should -BeLessThan 549755813887
$randomNumber | Should -BeGreaterThan 0
}
It "Should return false, check two random numbers are not equal when not using the SetSeed switch " {
$firstRandomNumber = Get-Random
$secondRandomNumber = Get-Random
$firstRandomNumber | Should -Not -Be $secondRandomNumber
$firstRandomNumber = Get-Random
$secondRandomNumber = Get-Random
$firstRandomNumber | Should -Not -Be $secondRandomNumber
}
It "Should return the same number for hexadecimal number and regular number when the switch SetSeed it used " {
$firstRandomNumber = Get-Random 0x07FFFFFFFF -SetSeed 20
$secondRandomNumber = Get-Random 34359738367 -SetSeed 20
$firstRandomNumber | Should -Be @secondRandomNumber
$firstRandomNumber = Get-Random 0x07FFFFFFFF -SetSeed 20
$secondRandomNumber = Get-Random 34359738367 -SetSeed 20
$firstRandomNumber | Should -Be @secondRandomNumber
}
It "Should throw an error because the hexadecimal number is to large " {
{ Get-Random 0x07FFFFFFFFFFFFFFFF } | Should -Throw "Value was either too large or too small for a UInt32"
{ Get-Random 0x07FFFFFFFFFFFFFFFF } | Should -Throw "Value was either too large or too small for a UInt32"
}
}