什么是PowerShell中的可扩展字符串 [英] What is an expandable string in PowerShell

问题描述

在PowerShell的文档，我遇到了表达式可扩展字符串:

In PowerShell's documentation, I have come across the expression expandable string:

参数模式设计用于解析Shell环境中命令的参数和参数.除非所有输入使用以下语法之一，否则它将被视为可扩展字符串:

不幸的是，我找不到可扩展字符串的定义，我的问题是:PowerShell中的可扩展字符串是什么?

Unfortunately, I am unable to find a definition for expandable string and my question is: what is an expandable string in PowerShell?

推荐答案

很遗憾，在撰写本文时，有关PowerShell字符串文字的官方帮助主题此GitHub文档PR ；在线版本将自动反映更改，但是要在本地也查看更改，您必须运行 更新帮助 .

It is definitely unfortunate that, as of this writing, the official help topic on PowerShell string literals, about_Quoting_Rules doesn't introduce the term expandable string; however, this will change soon: see this GitHub docs PR; the online version will reflect the changes automatically, but to see them locally as well, you'll have to run Update-Help.

可扩展字符串 为:

• 带有 double 且带引号的字符串 literal ("..." )

• 相比之下，用 引号的字符串('...')是 verbatim (文字)字符串；有关所有类型的PowerShell字符串文字的概述，其中包括 here-string 变体(例如， @"< newline> ...< newline>"@@ )，请参见此答案的底部.

• By contrast, a single-quoted string ('...') is a verbatim (literal) string; for an overview of all types of PowerShell string literals, which includes here-string variants (e.g., @"<newline>...<newline>"@), see the bottom section of this answer.

双引号字符串执行 字符串内插(扩展).

Double-quoted strings perform string interpolation (expansion).

• 这使您可以按原样嵌入简单的变量引用(例如，"$ var" )，并通过 $()嵌入表达式和整个语句(例如，"$($ var.property)" ).转义 verbatim $ (和" )字符.与`.将变量名称括在 {...} 中以消除歧义(例如，"$$ var}" ).有关完整的规则，请参见此答案.

• This allows you to embed simple variable references as-is (e.g, "$var"), and expressions and whole statements via $() (e.g., "$($var.property)"). Escape verbatim $ (and ") chars. with `. Enclose variable names in {...} for disambiguation (e.g. "${var}"). For the complete rules, see this answer.

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