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LINQ-ish Cmdlets for PowerShell
Raw
LINQ.psd1
@{
# MODULE
Description = 'LINQ for PowerShell'
ModuleVersion = '3.0'
GUID = '03BDA80F-0831-406E-B6AE-59E32D73F190'
# AUTHOR
Author = 'Josh Einstein'
CompanyName = 'Einstein Technologies'
Copyright = 'Copyright 2012 Einstein Technologies, LLC. All rights reserved.'
# REQUIREMENTS
PowerShellVersion = '2.0'
CLRVersion = '2.0.50727'
RequiredModules = @()
# CONTENTS
FormatsToProcess = @()
TypesToProcess = @()
RootModule = 'LINQ.psm1'
}
Raw
LINQ.psm1
##############################################################################
# SUMMARY
# Commands that add LINQ-like functionality to the PowerShell pipeline.
#
# NOTES
# PowerShell 2.0 will complain about the non-standard verb names.
# In short, I don't give a shit. I wanted the names to be consistent with
# LINQ and there isn't an appropriate verb that would cover all the
# functions. Feel free to rename as you see fit.
#
# AUTHOR
# Josh Einstein
#
# LICENSE
# Creative Commons License Deed
# Attribution-NonCommercial-ShareAlike 2.5
# http://creativecommons.org/licenses/by-sa/3.0/us/
##############################################################################
##############################################################################
# PUBLIC FUNCTIONS
##############################################################################
##############################################################################
#.SYNOPSIS
# Determines whether all elements of a sequence satisfy a condition.
#
#.DESCRIPTION
# This method does not return all the elements of a collection. Instead, it
# determines whether all the elements of a collection satisfy a condition.
#
# The predicate will stop being evaluated as soon as the result can be
# determined.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# An sequence that contains the elements to apply the predicate to.
#
#.EXAMPLE
# 1,2,3,4,5 | Linq-All { $_ -lt 6 }
##############################################################################
function Linq-All {
[CmdletBinding()]
param (
[Parameter(Position=1,Mandatory=$true)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$AllSoFar = $true
}
process {
# Short Circuit
# Stop checking once we found one negative
if (-not $AllSoFar) {
return
}
$AllSoFar = Test-Predicate $InputObject $Predicate
}
end {
$AllSoFar
}
}
##############################################################################
#.SYNOPSIS
# Determines whether any element of a sequence satisfies a condition.
#
#.DESCRIPTION
# This method does not return any one element of a collection. Instead, it
# determines whether any elements of a collection satisfy a condition.
#
# The predicate will stop being evaluated as soon as the result can be
# determined.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# An sequence that contains the elements to apply the predicate to.
#
#.EXAMPLE
# 1..10 | Linq-Any { $_ -gt 5 }
##############################################################################
function Linq-Any {
[CmdletBinding()]
param (
[Parameter(Position=1)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$AnySoFar = $false
}
process {
# Short Circuit
# Once we find one, stop checking
if ($AnySoFar) {
return
}
$AnySoFar = Test-Predicate $InputObject $Predicate
}
end {
$AnySoFar
}
}
##############################################################################
#.SYNOPSIS
# Returns a number that represents how many elements in the specified
# sequence satisfy a condition.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# A sequence that contains elements to be counted.
#
#.EXAMPLE
# 1..10 | Linq-Count { $_ -gt 5 }
##############################################################################
function Linq-Count {
[CmdletBinding()]
param (
[Parameter(Position=1)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Count = 0
}
process {
if (Test-Predicate $InputObject $Predicate) {
$Count += 1
}
}
end {
$Count
}
}
##############################################################################
#.SYNOPSIS
# Returns the first element in a sequence that satisfies a specified condition.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.EXAMPLE
# 1..10 | Linq-First { $_ -gt 5 }
##############################################################################
function Linq-First {
[CmdletBinding()]
param (
[Parameter(Position=1)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Count = 0
}
process {
if ($Count -gt 0) {
return
}
if (Test-Predicate $InputObject $Predicate) {
$Count += 1
$InputObject
}
}
}
##############################################################################
#.SYNOPSIS
# Returns the last element of a sequence that satisfies a specified condition.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.EXAMPLE
# 1..10 | Linq-Last { $_ -gt 5 }
##############################################################################
function Linq-Last {
[CmdletBinding()]
param (
[Parameter(Position=1)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Result = $null
$Count = 0
}
process {
if (Test-Predicate $InputObject $Predicate) {
$Count += 1
$Result = $InputObject
}
}
end {
if ($Count -gt 0) {
$Result
}
}
}
##############################################################################
#.SYNOPSIS
# Returns the only element of a sequence that satisfies a specified condition,
# and throws an exception if more than one or no such element exists.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.EXAMPLE
# 1..10 | Linq-Single { $_ -ge 10 }
##############################################################################
function Linq-Single {
[CmdletBinding()]
param (
[Parameter(Position=1)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Result = $null
$Count = 0
}
process {
if (Test-Predicate $InputObject $Predicate) {
if ($Count++ -gt 0) {
throw 'More than one element in the sequence matched the condition.'
}
$Result = $InputObject
}
}
end {
if ($Count -eq 1) {
$Result
}
}
}
##############################################################################
#.SYNOPSIS
# Bypasses a specified number of elements in a sequence and then returns the
# remaining elements.
#
#.DESCRIPTION
# If source contains fewer than count elements, an empty sequence is
# returned. If count is less than or equal to zero, all elements of source
# are yielded.
#
#.PARAMETER Count
# The number of elements to skip before returning the remaining elements.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.EXAMPLE
# 1..10 | Linq-Skip 5
##############################################################################
function Linq-Skip {
[CmdletBinding()]
param (
[Parameter(Position=1,Mandatory=$true)]
[Int64]$Count,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$ProcessCount = 0
}
process {
if ( ++$ProcessCount -gt $Count ) {
$InputObject
}
}
}
##############################################################################
#.SYNOPSIS
# Bypasses elements in a sequence as long as a specified condition is true and
# then returns the remaining elements.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.EXAMPLE
# 1..10 | Linq-SkipWhile { $_ -lt 5 }
##############################################################################
function Linq-SkipWhile {
[CmdletBinding()]
param (
[Parameter(Position=1,Mandatory=$true)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Result = $false
}
process {
if ( $Result -eq $true ) {
return $InputObject
}
if (-not (Test-Predicate $InputObject $Predicate)) {
$Result = $true
$InputObject
}
}
}
##############################################################################
#.SYNOPSIS
# Returns a specified number of contiguous elements from the start of a sequence.
#
#.DESCRIPTION
# If count is less than or equal to zero, source is not enumerated and an
# empty sequence is returned.
#
#.PARAMETER Count
# The number of elements to return.
#
#.PARAMETER InputObject
# The sequence to return elements from.
#
#.EXAMPLE
# 1..10 | Linq-Take 5
##############################################################################
function Linq-Take {
[CmdletBinding()]
param (
[Parameter(Position=1,Mandatory=$true)]
[Int64]$Count,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
[Int64]$ProcessCount = 0
}
process {
if ($ProcessCount++ -lt $Count) {
$InputObject
}
}
end {
}
}
##############################################################################
#.SYNOPSIS
# Returns elements from a sequence as long as a specified condition is true.
#
#.PARAMETER Predicate
# A function to test each element for a condition.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.EXAMPLE
# 1..10 | Linq-TakeWhile { $_ -lt 5 }
##############################################################################
function Linq-TakeWhile {
[CmdletBinding()]
param (
[Parameter(Position=1,Mandatory=$true)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Result = $true
}
process {
if ( $Result -eq $false ) { return }
if (Test-Predicate $InputObject $Predicate) {
$InputObject
}
else {
$Result = $false
}
}
}
##############################################################################
#.SYNOPSIS
# Creates a Hashtable from a sequence according to specified key selector and
# element selector functions.
#
#.PARAMETER KeySelector
# A function to extract a key from each element.
#
#.PARAMETER ValueSelector
# A transform function to produce a result element value from each element.
#
#.PARAMETER InputObject
# A sequence that contains elements to be tested.
#
#.PARAMETER Force
# If set, duplicate keys in the sequence will overwrite existing keys in
# the dictionary. The default behavior is to write an error if a duplicate
# key is detected.
#
#.EXAMPLE
# Get-Process | Linq-ToDictionary { $_.Id }
##############################################################################
function Linq-ToDictionary {
[CmdletBinding()]
param (
[Alias('k')]
[Parameter(Position=1,Mandatory=$true)]
[ScriptBlock]$KeySelector,
[Alias('v')]
[Parameter(Position=2)]
[ScriptBlock]$ValueSelector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject,
[Parameter()]
[Switch]$Force
)
begin {
$Result = @{}
}
process {
$Key = Invoke-Selector $InputObject $KeySelector
$Value = Invoke-Selector $InputObject $ValueSelector
if ($Result.ContainsKey($Key)) {
if ($Force) {
$Result[$Key] = $Value
}
else {
Write-Error "Duplicate key: $Key"
}
}
else {
$Result.Add($Key,$Value)
}
}
end {
$Result
}
}
##############################################################################
#.SYNOPSIS
# Creates a HashSet containing only unique items from a sequence.
#
#.PARAMETER Selector
#.PARAMETER InputObject
#.PARAMETER Type
##############################################################################
function Linq-ToSet {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Object]$Selector,
[Parameter()]
[Type]$Type = 'PSObject',
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
if ($Type -eq [String]) {
$Set = New-Object "System.Collections.Generic.HashSet[$Type]" @([System.StringComparer]::OrdinalIgnoreCase)
}
else {
$Set = New-Object "System.Collections.Generic.HashSet[$Type]"
}
}
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
[Void]$Set.Add($Selection)
}
}
end {
,$Set
}
}
##############################################################################
#.SYNOPSIS
# Excludes duplicated values from a sequence.
#
#.PARAMETER Selector
#.PARAMETER InputObject
##############################################################################
function Linq-Distinct {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Set = New-Object 'System.Collections.Generic.HashSet[PSObject]'
}
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ($Set.Add($Selection)) {
$Selection
}
}
}
}
##############################################################################
#.SYNOPSIS
# Repeats the input values a specified number of times.
#
#.PARAMETER Count
#.PARAMETER Selector
#.PARAMETER InputObject
##############################################################################
function Linq-Repeat {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Int32]$Count = 1,
[Parameter(Position=2)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
for ($i = 0; $i -lt $Count; $i++) {
$Selection
}
}
}
}
##############################################################################
#.SYNOPSIS
# Calculates the average of values in a sequence.
#.DESCRIPTION
#
#.PARAMETER Selector
#.PARAMETER InputObject
##############################################################################
function Linq-Average {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Sum = $null
$Count = 0
}
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ($Sum -ne $null) {
$Sum += $Selection
$Count += 1
}
else {
$Sum = $Selection
$Count = 1
}
}
}
end {
if ($Count -gt 0) {
$Sum/$Count
}
}
}
##############################################################################
#.SYNOPSIS
# Calculates the sum of values in a sequence.
#
#.PARAMETER Selector
#.PARAMETER InputObject
##############################################################################
function Linq-Sum {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Count = 0
$Sum = $null
}
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ($Sum -ne $null) {
$Sum += $Selection
$Count += 1
}
else {
$Sum = $Selection
$Count = 1
}
}
}
end {
if ($Count -gt 0) {
$Sum
}
}
}
##############################################################################
#.SYNOPSIS
# Calculates the maximum value in a sequence.
#
#.PARAMETER Selector
# If specified, selects a value to measure based on the input item.
# Otherwise, the input item itself will be measured.
#
#.PARAMETER InputObject
# The item to measure, typically passed from a pipeline.
##############################################################################
function Linq-Max {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Max = $null
}
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ( $Max -eq $null -or $Selection -gt $Max ) {
$Max = $Selection
}
}
}
end {
if ( $Max -ne $null ) { $Max }
}
}
##############################################################################
#.SYNOPSIS
# Calculates the minimum value in a sequence.
#
#.PARAMETER Selector
# If specified, selects a value to measure based on the input item.
# Otherwise, the input item itself will be measured.
#
#.PARAMETER InputObject
# The item to measure, typically passed from a pipeline.
##############################################################################
function Linq-Min {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$Min = $null
}
process {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ( $Min -eq $null -or $Selection -lt $Min ) {
$Min = $Selection
}
}
}
end {
if ( $Min -ne $null ) { $Min }
}
}
##############################################################################
#.SYNOPSIS
# Excludes from a sequence the items which also appear in a second sequence.
#
#.PARAMETER Sequence
#.PARAMETER InputObject
##############################################################################
function Linq-Except {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Array]$Sequence,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
process {
if ($Sequence -notcontains $InputObject) {
$InputObject
}
}
}
##############################################################################
#.SYNOPSIS
# Returns the items that exist in both the pipeline input and another
# collection.
#
#.PARAMETER Sequence
#.PARAMETER InputObject
##############################################################################
function Linq-Intersect {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[Array]$Sequence,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
process {
if ($Sequence -contains $InputObject) {
$InputObject
}
}
}
##############################################################################
#.SYNOPSIS
# Selects a property, property set, or ScriptBlock projection of the input.
#
#.DESCRIPTION
# This cmdlet has virtually no advantages over using ForEach-Object to
# project a value out to the pipeline, but I implemented it anyway because
# of some coding OCD I have.
#
#.PARAMETER Selector
# If specified, selects a value based on the input item.
# Otherwise, the input item itself will be selected.
#
#.PARAMETER InputObject
# The item to process, typically passed from a pipeline.
##############################################################################
function Linq-Select {
[CmdletBinding()]
param(
[Parameter(Position=1, Mandatory=$true)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
process {
Invoke-Selector $InputObject $Selector
}
}
##############################################################################
#.SYNOPSIS
# Similar to Linq-Select but always ensures the output is wrapped in an array.
#
#.PARAMETER Selector
# If specified, selects a value based on the input item.
# Otherwise, the input item itself will be selected.
# The difference between this and Linq-Select is that the output will always
# be an array even if the sequence only produces one object.
#
#.PARAMETER InputObject
# The item to process, typically passed from a pipeline.
##############################################################################
function Linq-SelectMany {
[CmdletBinding()]
param(
[Parameter(Position=1, Mandatory=$true)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
process {
,(Invoke-Selector $InputObject $Selector)
}
}
##############################################################################
#.SYNOPSIS
# Returns the zero-based position of the first element in a sequence that
# meets the specified criteria.
#
#.PARAMETER Selector
# The predicate that the found item must match.
#
#.PARAMETER InputObject
# The item to process, typically passed from a pipeline.
##############################################################################
function Linq-IndexOf {
[CmdletBinding()]
param(
[Parameter(Position=1,Mandatory=$true)]
[ScriptBlock]$Predicate,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$CurrentIndex = -1
$FoundIndex = -1
}
process {
$CurrentIndex += 1
if ( $FoundIndex -ge 0 ) { return }
if ( Test-Predicate $InputObject $Predicate ) {
$FoundIndex = $CurrentIndex
$FoundIndex
}
}
end {
if ($FoundIndex -eq -1) { -1 }
}
}
##############################################################################
#.SYNOPSIS
# Drills into an input object based on one or more property names to simplify
# access to data inside deep hierarchical structures.
#
#.DESCRIPTION
# This concept is somewhat difficult to describe and it has no corresponding
# feature in LINQ. A closer analogy would be XPath. Given an object that
# contains a property which is a collection of other objects, property names
# can be specified that cause Linq-Expand to evaluate a property, enumerate
# the items, select the next property, enumerate the items, and so on.
#
#.PARAMETER Property
# One or more property names that describes a path into the input object.
# Separate multiple property names with commas.
#
#.PARAMETER InputObject
# The item to process, typically passed from a pipeline.
#
#.EXAMPLE
# # where you typically do this...
# Get-Command | %{$_.ParameterSets} | %{$_.Parameters} | %{$_.Attributes} | %{$_.TypeId}
#
# # you can now do this...
# Get-Command | Expand ParameterSets,Parameters,Attributes,TypeId
##############################################################################
function Linq-Expand {
[CmdletBinding()]
param(
[Parameter(Position=1,Mandatory=$true)]
[String[]]$Property,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
process {
if ( $InputObject -eq $null ) { return }
$OutputObjects = @($InputObject)
foreach ($P in $Property) {
$OutputObjects = @($OutputObjects | %{ $_.$P })
}
$OutputObjects
}
}
##############################################################################
#.SYNOPSIS
# Returns items from a sequence whose selected values match one or more
# wildcard patterns.
#
#.DESCRIPTION
# This function uses the wildcard matching features of PowerShell to
# determine if the selected value matches one or more wildcard patterns
# and if so, the input object is passed along the pipeline.
#
# A particularly ugly piece of code is needed if you want to accept an array
# of strings for a parameter and allow the user to specify wildcards in them.
# Consider the -Include parameter of Get-ChildItem that allows you to specify
# wildcards such as:
#
# Get-ChildItem . -Include *.ps1,*.psm1
#
# The problem is you have to loop over the input set and loop over the
# patterns checking for a match on any of them. This function simplifies that
# process by rolling it into a single pipeline-aware cmdlet.
#
#.PARAMETER Pattern
# One or more wildcard patterns that will be matched against a value
# selected from the input object.
#
#.PARAMETER Selector
# Selects a property of the input object or some other value based on the
# input object to be tested against the patterns. If not specified, the
# input object itself is matched.
#
#.PARAMETER InputObject
# The object to test against the pattern.
#
#.PARAMETER Not
# If specified, the meaning of the pattern is inverted and only items not
# matching any of the patterns are returned.
#
#.EXAMPLE
# Get-Process | Like sql*,sharepoint*
#
#.LINK
# Linq-WhereMatch
##############################################################################
function Where-Like {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[String[]]$Pattern,
[Parameter(Position=2)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject,
[Parameter()]
[Switch]$Not
)
process {
if ($Pattern.Length) {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ($Not) {
for ($i=0; $i -lt $Pattern.Length; $i++) {
if ($Selection -notlike $Pattern[$i]) {
}
else {
return
}
}
return $InputObject
}
else {
for ($i=0; $i -lt $Pattern.Length; $i++) {
if ($Selection -like $Pattern[$i]) {
return $InputObject
}
}
}
}
}
else {
return $InputObject
}
}
}
##############################################################################
#.SYNOPSIS
# Returns items from a sequence whose selected values match one or more
# regular expression patterns.
#
#.DESCRIPTION
# This function uses the regular expression features of PowerShell to
# determine if the selected value matches one or more regex patterns
# and if so, the input object is passed along the pipeline.
#
# A particularly ugly piece of code is needed if you want to accept an array
# of strings for a parameter and allow the user to specify wildcards in them.
# Consider the -Include parameter of Get-ChildItem that allows you to specify
# wildcards such as:
#
# Get-ChildItem . -Include *.ps1,*.psm1
#
# The problem is you have to loop over the input set and loop over the
# patterns checking for a match on any of them. This function simplifies that
# process by rolling it into a single pipeline-aware cmdlet.
#
#.PARAMETER Pattern
# One or more regular expression patterns that will be matched against a value
# selected from the input object.
#
#.PARAMETER Selector
# Selects a property of the input object or some other value based on the
# input object to be tested against the patterns. If not specified, the
# input object itself is matched.
#
#.PARAMETER InputObject
# The object to test against the pattern.
#
#.PARAMETER Not
# If specified, the meaning of the pattern is inverted and only items not
# matching any of the patterns are returned.
#
#.EXAMPLE
# Get-Process | Match sql.*,sharepoint.*
#
#.LINK
# Linq-WhereLike
##############################################################################
function Where-Match {
[CmdletBinding()]
param(
[Parameter(Position=1)]
[String[]]$Pattern,
[Parameter(Position=2)]
[Object]$Selector,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject,
[Parameter()]
[Switch]$Not,
[Parameter()]
[Switch]$IgnoreNull
)
process {
if ($Pattern.Length) {
if ($Selection = Invoke-Selector $InputObject $Selector) {
if ($Not) {
for ($i=0; $i -lt $Pattern.Length; $i++) {
if ($Selection -notmatch $Pattern[$i]) {
}
else {
return
}
}
return $InputObject
}
else {
for ($i=0; $i -lt $Pattern.Length; $i++) {
if ($Selection -match $Pattern[$i]) {
return $InputObject
}
}
}
}
}
else {
return $InputObject
}
}
}
##############################################################################
# PRIVATE FUNCTIONS
##############################################################################
# It is actually surprisingly difficult to write a function (in a module)
# that uses $_ in scriptblocks that it takes as parameters. This is a strange
# issue with scoping that seems to only matter when the function is a part
# of a module which has an isolated scope.
#
# In the case of this code:
# 1..10 | Add-Ten { $_ + 10 }
#
# ... the function Add-Ten must jump through hoops in order to invoke the
# supplied scriptblock in such a way that $_ represents the current item
# in the pipeline.
#
# Which brings me to Invoke-ScriptBlock.
# This function takes a ScriptBlock as a parameter, and an object that will
# be supplied to the $_ variable. Since the $_ may already be defined in
# this scope, we need to store the old value, and restore it when we are done.
# Unfortunately this can only be done (to my knowledge) by hitting the
# internal api's with reflection. Not only is this an issue for performance,
# it is also fragile. Fortunately this appears to still work in PowerShell
# version 2 through 3 beta.
# No warranties expressed or implied.
function Invoke-ScriptBlock {
[CmdletBinding()]
param (
[Parameter(Position=1,Mandatory=$true)]
[ScriptBlock]$ScriptBlock,
[Parameter(ValueFromPipeline=$true)]
[Object]$InputObject
)
begin {
$SessionStateProperty = [ScriptBlock].GetProperty('SessionState',([System.Reflection.BindingFlags]'NonPublic,Instance'))
$SessionState = $SessionStateProperty.GetValue($ScriptBlock, $null)
}
process {
$NewUnderBar = $InputObject
$OldUnderBar = $SessionState.PSVariable.GetValue('_')
try {
$SessionState.PSVariable.Set('_', $NewUnderBar)
$SessionState.InvokeCommand.InvokeScript($SessionState, $ScriptBlock, @())
}
finally {
$SessionState.PSVariable.Set('_', $OldUnderBar)
}
}
}
function Invoke-Selector($InputObject, [Object]$Selector) {
if ($Selector -is [ScriptBlock]) {
Invoke-ScriptBlock -InputObject:$InputObject -ScriptBlock:$Selector
}
elseif ($Selector -is [String]) {
$InputObject.$Selector
}
elseif ($Selector -is [String[]]) {
Select-Object -InputObject:$InputObject -Property:$Selector
}
elseif ($Selector -eq $null) {
$InputObject
}
else {
throw 'Selector must be a ScriptBlock, an individual property, or a property set.'
}
}
function Test-Predicate($InputObject, [Object]$Predicate) {
if ($Predicate) {
if (Invoke-ScriptBlock -InputObject:$InputObject -ScriptBlock:$Predicate ) {
return $true
}
else {
return $false
}
}
else {
return $true # no predicate always includes inputobject
}
}
##############################################################################
# EXPORTS
##############################################################################
Export-ModuleMember -Function Linq-All
Export-ModuleMember -Function Linq-Any
Export-ModuleMember -Function Linq-Average
Export-ModuleMember -Function Linq-Count
Export-ModuleMember -Function Linq-Distinct
Export-ModuleMember -Function Linq-Except
Export-ModuleMember -Function Linq-Expand
Export-ModuleMember -Function Linq-First
Export-ModuleMember -Function Linq-IndexOf
Export-ModuleMember -Function Linq-Intersect
Export-ModuleMember -Function Linq-Last
Export-ModuleMember -Function Linq-Max
Export-ModuleMember -Function Linq-Min
Export-ModuleMember -Function Linq-Repeat
Export-ModuleMember -Function Linq-Select
Export-ModuleMember -Function Linq-SelectMany
Export-ModuleMember -Function Linq-Single
Export-ModuleMember -Function Linq-Skip
Export-ModuleMember -Function Linq-SkipWhile
Export-ModuleMember -Function Linq-Sum
Export-ModuleMember -Function Linq-Take
Export-ModuleMember -Function Linq-TakeWhile
Export-ModuleMember -Function Linq-ToDictionary
Export-ModuleMember -Function Linq-ToSet
Export-ModuleMember -Function Where-Match
Export-ModuleMember -Function Where-Like
Raw
Test-LINQ.ps1
Import-Module LINQ
function Assert-AreEqual($Expected, $Actual) {
if (@(Compare-Object $Expected $Actual -SyncWindow 0).Length) {
$OFS = ','
Write-Error "Assert-AreEqual Failed: Expected=($Expected), Actual=($Actual)"
}
}
# All
Assert-AreEqual -Expected ($true) -Actual (1..5 | Linq-All { $_ -gt 0 })
Assert-AreEqual -Expected ($false) -Actual (1..5 | Linq-All { $_ -gt 6 })
Assert-AreEqual -Expected ($true) -Actual (@() | Linq-All { $_ -gt 6 })
# Any
Assert-AreEqual -Expected ($true) -Actual (1..5 | Linq-Any)
Assert-AreEqual -Expected ($false) -Actual (@() | Linq-Any)
Assert-AreEqual -Expected ($true) -Actual (1..5 | Linq-Any { $_ -eq 3 })
Assert-AreEqual -Expected ($false) -Actual (1..5 | Linq-Any { $_ -eq 6 })
# First
Assert-AreEqual -Expected @(1) -Actual @(1..5 | Linq-First)
Assert-AreEqual -Expected @(2) -Actual @(1..5 | Linq-First { $_ -gt 1 })
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-First { $_ -gt 5 })
# Last
Assert-AreEqual -Expected @(5) -Actual @(1..5 | Linq-Last)
Assert-AreEqual -Expected @(4) -Actual @(1..5 | Linq-Last { $_ -lt 5 })
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Last { $_ -lt 1 })
# Single
Assert-AreEqual -Expected @(2) -Actual @(1..5 | Linq-Single { $_ -eq 2 })
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Single { $_ -gt 5 })
# Skip
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Skip 0)
Assert-AreEqual -Expected @(3..5) -Actual @(1..5 | Linq-Skip 2)
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Skip 5)
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Skip 6)
# SkipWhile
Assert-AreEqual -Expected @(2..5) -Actual @(1..5 | Linq-SkipWhile { $_ -eq 1})
Assert-AreEqual -Expected @(3..5) -Actual @(1..5 | Linq-SkipWhile { $_ -lt 3})
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-SkipWhile { $false })
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-SkipWhile { $true })
# Take
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Take 5)
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Take 6)
Assert-AreEqual -Expected @(1..5) -Actual @(1..6 | Linq-Take 5)
Assert-AreEqual -Expected @(1..3) -Actual @(1..5 | Linq-Take 3)
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Take 0)
# TakeWhile
Assert-AreEqual -Expected @(1..2) -Actual @(1..5 | Linq-TakeWhile { $_ -lt 3})
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-TakeWhile { $_ -eq 2})
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-TakeWhile { $false })
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-TakeWhile { $true })
# Distinct
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Distinct)
Assert-AreEqual -Expected @(1..5) -Actual @(1,2,3,4,5,1,2,3,4,5 | Linq-Distinct)
Assert-AreEqual -Expected @() -Actual @(Linq-Distinct)
# Repeat
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Repeat 1)
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Repeat 0)
Assert-AreEqual -Expected @(1,1,2,2,3,3,4,4,5,5) -Actual @(1..5 | Linq-Repeat 2)
# Except
Assert-AreEqual -Expected @(1,3,5) -Actual @(1..5 | Linq-Except (2,4))
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Except 6)
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Except (1..5))
# Intersect
Assert-AreEqual -Expected @(2,4) -Actual @(1..5 | Linq-Intersect (2,4))
Assert-AreEqual -Expected @() -Actual @(1..5 | Linq-Intersect 6)
Assert-AreEqual -Expected @(1..5) -Actual @(1..5 | Linq-Intersect (1..5))
# IndexOf
Assert-AreEqual -Expected (0) -Actual (1..5 | Linq-IndexOf { $_ -eq 1 })
Assert-AreEqual -Expected (3) -Actual (1..5 | Linq-IndexOf { $_ -eq 4 })
Assert-AreEqual -Expected (-1) -Actual (1..5 | Linq-IndexOf { $_ -eq 6 })
Assert-AreEqual -Expected (2) -Actual (1,2,3,3,3 | Linq-IndexOf { $_ -eq 3 })
# Count
Assert-AreEqual -Expected (5) -Actual (1..5 | Linq-Count)
Assert-AreEqual -Expected (1) -Actual (1..5 | Linq-Count { $_ -eq 3 })
Assert-AreEqual -Expected (0) -Actual (1..5 | Linq-Count { $_ -eq 6 })
# Average, Min, Max
Assert-AreEqual -Expected (3) -Actual (1..5 | Linq-Average)
Assert-AreEqual -Expected (15) -Actual (1..5 | Linq-Sum)
Assert-AreEqual -Expected (5) -Actual (1..5 | Linq-Max)
Assert-AreEqual -Expected (1) -Actual (1..5 | Linq-Min)
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