我有两个PowerShell函数,第一个调用第二个函数。它们都带有N个参数,其中一个被定义为简单地添加一个标志并调用另一个。以下是示例定义:
function inner
{
foreach( $arg in $args )
{
# do some stuff
}
}
function outer
{
inner --flag $args
}
用法看起来像这样:
inner foo bar baz
或者
outer wibble wobble wubble
目标是后一个例子等同于
inner --flag wibble wobble wubble
问题:如此处所定义,后者实际上导致两个参数传递给inner
:第一个是“--flag”,第二个是包含“晃动“,”摇晃“和”喧闹“。我想要的是inner
接收四个参数:标志和三个原始参数。
所以我想知道如何说服powershell扩展$ args数组,然后将其传递给inner
,将其作为N个元素而不是单个数组传递。我相信你可以使用splatting运算符(*字符)在Ruby中执行此操作,我很确定PowerShell可以做到这一点,但我不记得如何。
答案 0 :(得分:11)
PowerSHell V1中没有很好的解决方案。在V2中我们添加了splatting(虽然出于各种原因,我们使用@而不是*来实现此目的)。这是它的样子:
PS(STA-ISS)(2)> function foo($ x,$ y,$ z){“x:$ x y:$ y z:$ z”}
PS(STA-ISS)(3)> $ a = 1,2,3
PS(STA-ISS)(4)> foo $ a#作为单个arg传递
x:1 2 3 y:z:
PS(STA-ISS)(5)> foo @a #splatted
x:1 y:2 z:3
答案 1 :(得分:0)
嗯,可能有更好的方法,但看看是否有效:
inner --flag [string]::Join(" ", $args)
答案 2 :(得分:0)
基于@ EBGreen的想法,以及我在侧边栏中注意到的相关问题,可能的解决方案是:
function outer
{
invoke-expression "inner --flag $($args -join ' ')"
}
注意:此示例使用Powershell 2.0 CTP的新-join
运算符。
然而,我仍然希望找到一个更好的方法,因为这感觉就像一个黑客,并且在安全方面是可怕的。
答案 3 :(得分:0)
如果您想要一个快速的现成解决方案,您可以复制粘贴我的:
<#
.SYNOPSIS
Asks a question and waits for user's answer
.EXAMPLE
Usage with shortcuts and without ReturnValue
Invoke-Question -Question "What would you like" -Answers "&Eggs", "&Toasts", "&Steak"
Shows the quesiton and waits for input. Let's assume user input is 'S', the return value would be 2 (index of "&Steak")
.EXAMPLE
Usage without shortcuts and with ReturnValue
Invoke-Question -Question "What would you like" -Answers "Eggs", "Toasts", "Steak" -ReturnValue
Shows the quesiton and waits for input. The answers are prefixed with numbers 1, 2 and 3 as shortcuts.
Let's assume user input is 2, the return value would be "Toasts" (prefixed numbers are "index + 1")
.EXAMPLE
Usage from pipeline with default value
@("Eggs", "Toasts", "Steak") | Invoke-Question -Question "What would you like" -ReturnValue -Default 2
Shows the quesiton and waits for input. The answers are taken from pipeline and prefixed with numbers 1, 2 and 3 as shortcuts.
Steak is marked as default. If user simply continues without a choice, Steak is chosen for her.
However, let's assume user input is 1, the return value would be "Eggs" (prefixed numbers are "index + 1")
#>
function Invoke-Question {
[CmdletBinding()]
param(
# Main question text
[Parameter(Mandatory = $true)]
[string] $Question,
# Question description, e.g. explanation or more information
[Parameter(Mandatory = $false)]
[string] $Description = "",
# Default answer as index in the array, no answer is selected by default (value -1)
[Parameter(Mandatory = $false)]
[int] $Default = -1,
# Set of answers, if the label is given with & sign, the prefixed letter is used as shortcut, e.g. "&Yes" -> Y,
# otherwise the answer is prefixed with "index + 1" number as a shortcut
[Parameter(Mandatory = $true, ValueFromPipeline = $true)]
[string[]] $Answers,
# If set, returns a value of selected answer, otherwise returns its index in the Answer array
[switch] $ReturnValue
)
begin {
# init choices
$choices = New-Object Collections.ObjectModel.Collection[Management.Automation.Host.ChoiceDescription]
$answerNumber = 1
$rememberAnswers = @()
}
process {
#init answers
foreach ($answer in $answers) {
$rememberAnswers += $answer
if ($answer -notmatch "&") {
# add number if shortcut not specified
$answer = "&$answerNumber $answer"
}
$choices.Add((New-Object Management.Automation.Host.ChoiceDescription -ArgumentList $answer))
$answerNumber++
}
}
end {
# ask question and return either value or index
$index = $Host.UI.PromptForChoice($Question, $Description, $choices, $Default)
if ($ReturnValue) {
$rememberAnswers[$index]
} else {
$index
}
}
}