benchmark-dictionary vs hashtable.ps1

#requires -Module BenchPress

using namespace System.Collections
using namespace System.Collections.Generic

$ran = [random]::new()

$dataset = foreach($i in 1..100000) {
    [pscustomobject]@{
        Val = $ran.Next(1, $i)
    }
}

Measure-Benchmark -GroupName "Hashtable vs Dictionary (int Keys)" -RepeatCount 2 -Technique @{
    'Hashtable + Object[]' = {
        $map = @{}
        foreach($i in $dataset)
        {
            if($val = $map[$i.Val])
            {
                $map[$i.Val] = $val + $i
                continue
            }

            $map[$i.Val] = ,$i
        }
    }
    'Dictionary + Object[]' = {
        $dict = [Dictionary[string, object]]::new()

        foreach($i in $dataset)
        {
            if($val = $dict[$i.Val])
            {
                $dict[$i.Val] = $val + $i
                continue
            }
            $dict[$i.Val] = ,$i
        }
    }
    'Hashtable + List`1' = {
        $map = @{}
        foreach($i in $dataset)
        {
            if($val = $map[$i.Val])
            {
                $val.Add($i)
                continue
            }

            $map[$i.Val] = [List[object]]::new()
            $map[$i.Val].Add($i)
        }
    }
    'Dictionary + ArrayList' = {
        $dict = [Dictionary[string, ArrayList]]::new()
        foreach($i in $dataset)
        {
            if($val = $dict[$i.Val])
            {
                $null = $val.Add($i)
                continue
            }
            $null = $dict.Add($i.Val, @($i))
        }
    }
    'Group Object -AsHashTable' = {
        $groupObj = $dataset | Group-Object Val -AsHashTable -AsString
    }
}

$dataset = foreach($i in 1..100000) {
    [pscustomobject]@{
        Val = -join [char[]](0..2 | ForEach-Object { $ran.Next(65, 90) })
    }
}

Measure-Benchmark -GroupName "Hashtable vs Dictionary (string Keys)" -RepeatCount 2 -Technique @{
    'Hashtable + Object[]' = {
        $map = @{}
        foreach($i in $dataset)
        {
            if($val = $map[$i.Val])
            {
                $map[$i.Val] = $val + $i
                continue
            }

            $map[$i.Val] = ,$i
        }
    }
    'Dictionary + Object[]' = {
        $dict = [Dictionary[string, object]]::new()

        foreach($i in $dataset)
        {
            if($val = $dict[$i.Val])
            {
                $dict[$i.Val] = $val + $i
                continue
            }
            $dict[$i.Val] = ,$i
        }
    }
    'Hashtable + List`1' = {
        $map = @{}
        foreach($i in $dataset)
        {
            if($val = $map[$i.Val])
            {
                $val.Add($i)
                continue
            }

            $map[$i.Val] = [List[object]]::new()
            $map[$i.Val].Add($i)
        }
    }
    'Dictionary + ArrayList' = {
        $dict = [Dictionary[string, ArrayList]]::new()
        foreach($i in $dataset)
        {
            if($val = $dict[$i.Val])
            {
                $null = $val.Add($i)
                continue
            }
            $null = $dict.Add($i.Val, @($i))
        }
    }
    'Group Object -AsHashTable' = {
        $groupObj = $dataset | Group-Object Val -AsHashTable -AsString
    }
}

$ran = [random]::new()
$dataset = foreach($i in 1..100000) {
    [pscustomobject]@{
        Key = -join [char[]](0..2 | ForEach-Object { $ran.Next(65, 70) })
        Val = $ran.Next()
    }
}

Measure-Benchmark -GroupName "Hashtable vs Dictionary (Multiple Collisions)" -RepeatCount 2 -Technique @{
    'Hashtable + Object[]' = {
        $map = @{}
        foreach($i in $dataset)
        {
            if($val = $map[$i.Key])
            {
                $map[$i.Key] = $val + $i
                continue
            }
            $map[$i.Key] = ,$i
        }
    }
    'Dictionary + Object[]' = {
        $dict = [Dictionary[string, object]]::new()

        foreach($i in $dataset)
        {
            if($val = $dict[$i.Key])
            {
                $dict[$i.Key] = $val + $i
                continue
            }
            $dict[$i.Key] = ,$i
        }
    }
    'Hashtable + List`1' = {
        $map = @{}
        foreach($i in $dataset)
        {
            if($val = $map[$i.Key])
            {
                $val.Add($i)
                continue
            }

            $map[$i.Key] = [List[object]]::new()
            $map[$i.Key].Add($i)
        }
    }
    'Dictionary + ArrayList' = {
        $dict = [Dictionary[string, ArrayList]]::new()
        foreach($i in $dataset)
        {
            if($val = $dict[$i.Key])
            {
                $null = $val.Add($i)
                continue
            }
            $null = $dict.Add($i.Key, @($i))
        }
    }
    'Group Object -AsHashTable' = {
        $groupObj = $dataset | Group-Object Key -AsHashTable -AsString
    }
}