string 使用 PowerShell 拆分字符串并对每个令牌执行某些操作
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Split string with PowerShell and do something with each token
提问by Pieter Müller
I want to split each line of a pipe on spaces, and then print each token on its own line.
我想在空格上拆分管道的每一行，然后在自己的行上打印每个标记。
I realise that I can get this result using:
我意识到我可以使用以下方法得到这个结果：
(cat someFileInsteadOfAPipe).split(" ")
But I want more flexibility. I want to be able to do just about anything with each token. (I used to use AWKon Unix, and I'm trying to get the same functionality.)
但我想要更多的灵活性。我希望能够对每个令牌做任何事情。（我曾经在 Unix上使用AWK，我正在尝试获得相同的功能。）
I currently have:
我目前有：
echo "Once upon a time there were three little pigs" | %{$data = $_.split(" "); Write-Output "$($data[0]) and whatever I want to output with it"}
Which, obviously, only prints the first token. Is there a way for me to for-each over the tokens, printing each in turn?
显然，它只打印第一个标记。有没有办法让我对令牌进行 for-each，依次打印？
Also, the %{$data = $_.split(" "); Write-Output "$($data[0])"}part I got from a blog, and I really don't understand what I'm doing or how the syntax works.
另外，%{$data = $_.split(" "); Write-Output "$($data[0])"}我从博客中得到的部分，我真的不明白我在做什么或语法是如何工作的。
I want to google for it, but I don't know what to call it. Please help me out with a word or two to Google, or a link explaining to me what the %and all the $symbols do, as well as the significance of the opening and closing brackets.
我想用谷歌搜索它，但我不知道该怎么称呼它。请帮我用一两个词到谷歌，或者一个链接，向我解释%这些$符号和所有符号的作用，以及左括号和右括号的意义。
I realise I can't actually use (cat someFileInsteadOfAPipe).split(" "), since the file (or preferable incoming pipe) contains more than one line.
我意识到我实际上不能使用(cat someFileInsteadOfAPipe).split(" ")，因为文件（或更好的传入管道）包含不止一行。
Regarding some of the answers:
关于一些答案：
If you are using Select-Stringto filter the output before tokenizing, you need to keep in mind that the output of the Select-Stringcommand is not a collection of strings, but a collection of MatchInfoobjects. To get to the string you want to split, you need to access the Lineproperty of the MatchInfoobject, like so:
如果Select-String在标记化之前使用过滤输出，则需要记住Select-String命令的输出不是字符串集合，而是MatchInfo对象集合。要获得要拆分的字符串，您需要访问对象的Line属性MatchInfo，如下所示：
cat someFile | Select-String "keywordFoo" | %{$_.Line.Split(" ")}
回答by Justus Thane
"Once upon a time there were three little pigs".Split(" ") | ForEach {
"$_ is a token"
}
The key is $_, which stands for the current variable in the pipeline.
关键是$_，它代表管道中的当前变量。
About the code you found online:
关于您在网上找到的代码：
%is an alias for ForEach-Object. Anything enclosed inside the brackets is run once for each object it receives. In this case, it's only running once, because you're sending it a single string.
%是 的别名ForEach-Object。括号内的任何内容都对其接收到的每个对象运行一次。在这种情况下，它只运行一次，因为您发送的是单个字符串。
$_.Split(" ")is taking the current variable and splitting it on spaces. The current variable will be whatever is currently being looped over by ForEach.
$_.Split(" ")正在获取当前变量并将其拆分为空格。当前变量将是当前正在循环的任何内容ForEach。
回答by mklement0
To complement Justus Thane's helpful answer:
为了补充Justus Thane 的有用回答：
As Joeynotes in a comment, PowerShell has a powerful, regex-based
-splitoperator.- In its unaryform (
-split '...'),-splitbehaves likeawk's default field splitting, which means that:- Leading and trailing whitespace is ignored.
- Any runof whitespace (e.g., multipleadjacent spaces) is treated as a singleseparator.
- In its unaryform (
In PowerShell v4+an expression-based - and therefore faster - alternative to the
ForEach-Objectcmdletbecame available: the.ForEach()array (collection) method, as described in this blog post(alongside the.Where()method, a more powerful, expression-based alternative toWhere-Object).
正如Joey在评论中指出的那样，PowerShell 有一个强大的、基于正则表达式的
-split运算符。- 在其一元形式 (
-split '...') 中，-split其行为类似于awk的默认字段拆分，这意味着：- 忽略前导和尾随空格。
- 任何运行空格（例如，多个相邻空间）被视为一单一隔板。
- 在其一元形式 (
在PowerShell v4+ 中，可以使用基于表达式（因此速度更快）的
ForEach-Objectcmdlet替代.ForEach()方法：数组（集合）方法，如本博客文章中所述（除了该.Where()方法，更强大的基于表达式的替代方法Where-Object）。
Here's a solution based on these features:
这是基于这些功能的解决方案：
PS> (-split ' One for the money ').ForEach({ "token: [$_]" })
token: [One]
token: [for]
token: [the]
token: [money]
Note that the leading and trailing whitespace was ignored, and that the multiple spaces between Oneand forwere treated as a single separator.
注意，开头和结尾的空白将被忽略，而之间的多个空格One和for被视为一个单一的分隔符。
回答by s31064
Another way to accomplish this is a combination of Justus Thane's and mklement0's answers. It doesn't make sense to do it this way when you look at a one liner example, but when you're trying to mass-edit a file or a bunch of filenames it comes in pretty handy:
实现此目的的另一种方法是结合 Justus Thane 和 mklement0 的答案。当您查看单行示例时，这样做没有意义，但是当您尝试批量编辑一个文件或一堆文件名时，它会非常方便：
$test = ' One for the money '
$option = [System.StringSplitOptions]::RemoveEmptyEntries
$($test.split(' ',$option)).foreach{$_}
This will come out as:
这将显示为：
One
for
the
money
回答by js2010
-split outputs an array, and you can save it to a variable like this:
-split 输出一个数组，您可以将其保存到这样的变量中：
$a = -split 'Once upon a time'
$a[0]
Once
Another cute thing, you can have arrays on both sides of an assignment statement:
另一个可爱的事情，你可以在赋值语句的两边都有数组：
$a,$b,$c = -split 'Once upon a'
$c
a
