通过重新格式化现有文件名来重命名文件-与-replace运算符一起使用的替换字符串中的占位符 [英] Renaming files by reformatting existing filenames - placeholders in replacement strings used with the -replace operator

问题描述

我有一些这样的视频文件: VideoName_s01e01.mp4，其中季节和情节是变量.我想在s??和e??之间添加下划线(_).

I have a few video file like this: VideoName_s01e01.mp4 where the season and episodes are variables. I want to add an underscore ("_") between the s?? and e??.

我一直在使用 powershell 的问题进行重命名，我有一个起点:

I have been using powershell for renaming purposes, I have a starting point:

GCI $path -filter '*_s??e??*' -rec |  Ren -new { $_.name -replace '_s[0-9][0-9]', '_s[0-9]_[0-9]_' } -passthru    

这实际上重命名了我的文件VideoName_s[0-9]_e[0-9].mp4.

This actually renamed my files VideoName_s[0-9]_e[0-9].mp4.

基本上，我正在寻找字符s??e??，我只是不知道如何在替换部分中使它们成为变量.

Basically, I am looking for the characters s??e?? I just don't know how to make them variables in the replace section.

我认为最好的方法是:

1. 找到e??s??的位置(我们称它为X).
2. 在X-3处分割字符串.
3. 将字符串与中间的"_"连接起来.

1. Find the position of e??s?? (let's call it X).
2. split the string at X-3.
3. concatenate the string with a "_" in the middle.

推荐答案

Martin Brandl的回答提供了一种优雅而有效的解决方案 ，但值得深入研究:

Martin Brandl's answer provides an elegant and effective solution, but it's worth digging deeper:

PowerShell的-replace运算符(... -replace <search>[, <replace>]):

PowerShell's -replace operator (... -replace <search>[, <replace>]):

• 采用 正则表达式 作为其第一个操作数<search>(搜索表达式)，并且始终匹配 global ，即，它替换 all 匹配项

• Takes a regular expression as its first operand, <search> (the search expression), and invariably matches globally, i.e., it replaces all matches.

• 'bar' -replace '[ra]', '@'-> 'b@@'

• 'bar' -replace '[ra]', '@' -> 'b@@'

指定替换表达式<replace>是可选，在这种情况下，空字符串将替换为<search>匹配的内容，从而导致有效的删除.

Specifying a replacement expression, <replace>, is optional, in which case the empty string is substituted for what <search> matched, resulting in its effective removal.

• 'bar' -replace '[ra]'-> 'b'

• 'bar' -replace '[ra]' -> 'b'

如果指定了<replace> ，则支持两种形式:

If <replace> is specified, it supports two forms:

• v6.1 + (仅适用于PowerShell Core ):一个 script块({ ... })作为替换操作数，可以在每次匹配的基础上完全动态地计算替换字符串-例如，请参见此答案.

• v6.1+ (PowerShell Core only): A script block ({ ... }) as the replacement operand, which offers fully dynamic calculation of the replacement string on a per-match basis - see this answer for an example.

• 'bar' -replace '[ra]', { '{' + $_.Value + '}' }-> 'b{a}{r}'

• 'bar' -replace '[ra]', { '{' + $_.Value + '}' } -> 'b{a}{r}'

一个字符串，其中包含一个表达式，该表达式可以引用正则表达式捕获(和未捕获)的内容，

A string containing an expression that can reference what the regular expression captured (and didn't capture), explained below.

• 'bar' -replace '[ra]', '{$&}'-> 'b{a}{r}'

• 'bar' -replace '[ra]', '{$&}' -> 'b{a}{r}'

-replace不区分大小写匹配- (也可以写为-ireplace)；要执行区分大小写的 匹配，请使用-creplace形式.

-replace matches case-insensitively (and can also be written as -ireplace); to perform case-sensitive matching, use the form -creplace.

替换语言"用于在字符串类型的<replace>操作数中引用正则表达式捕获的对象本身不是正则表达式-此处不存在匹配项，仅引用结果 >支持的正则表达式匹配.

The "replacement language" for referencing regex captures in a string-typed <replace> operand is itself not a regular expression - no matching happens there, only references to the results of the regex matching are supported.

值得注意的是，

• PowerShell不会不在其

• PowerShell does not explain the syntax of replacement strings in its Get-Help about_comparison_operators help topic,

，但可以在正则表达式中的替换 .NET框架帮助主题，因为PowerShell的-replace使用

but the information can be found in the Substitutions in Regular Expressions .NET framework help topic, because PowerShell's -replace uses the Regex.Replace() method behind the scenes.

为方便起见，这是<replace>字符串中受支持的引用(摘录自上面链接的页面，并添加了重点和注释):

For convenience, here are the references supported in the <replace> string (excerpted from the page linked above, with emphasis and annotations added):

• $number(例如，$1)...包括由基于1的number 标识的捕获组匹配的最后一个子字符串，其中数字是替换字符串中的十进制值.

• $number (e.g., $1) ... Includes the last substring matched by the capture group that is identified by the 1-based number, where number is a decimal value, in the replacement string.

• 注释:

  • 在正则表达式中包含带括号的子表达式(...)会隐式创建一个捕获组(捕获组).默认情况下，此类捕获组为未命名，并且必须通过其基于1的(十进制) index 进行引用，以反映它们在正则表达式中出现的顺序，以便$1指的是正则表达式中第一个组所捕获的内容，$2指的是第二个组中所捕获的内容，...

  • Annotations:

    • Including (...), a parenthesized subexpression, in the regex implicitly creates a capture group (capturing group). By default, such capture groups are unnamed and must be referenced by their 1-based (decimal) index reflecting the order in which they appear in the regex, so that $1 refers to what the 1st group in your regex captured, $2 to what the 2nd captured, ...

    数字的消除歧义的格式${number}(例如，${1})也受支持(例如，即使后跟，也要确保识别出$1，例如000，请使用${1}000).

    The form ${number} (e.g., ${1}) for disambiguation of the number is also supported (e.g., to make sure that $1 is recognized even if followed by, say, 000, use ${1}000).

    您可以命名命名捕获组并按名称引用它们，而不是依赖索引来引用它们-请参阅下一点.

    Instead of relying on indices to refer to unnamed capture groups, you can name capture groups and refer to them by name - see next point.

    如果您对捕获组匹配的内容不感兴趣，则可以选择忽略它，方法是使用(?:...)将其变成一个非捕获组.

    If you're not interested in what the capture group matched, you can opt to ignore it by turning it into a non-capturing group with (?:...).

    ${name} ... ...在替换字符串中包括由(?<name>...)指定的命名组匹配的最后一个子字符串.

    ${name} ... Includes the last substring matched by the named group that is designated by (?<name>...) in the replacement string.

    $$ ...在替换字符串中包含单个 "$"文字.

    $$ ... Includes a single "$" literal in the replacement string.

    $& ...在替换字符串中包含整个匹配项的副本($0也可以，即使

    $& ... Includes a copy of the entire match in the replacement string ($0 works too, even though it isn't directly documented).

    $` ... ...将替换字符串中输入字符串 之前的所有文本包括在内.

    $` ... Includes all the text of the input string before the match in the replacement string.

    $' ...在匹配字符串中包含输入字符串 之后的所有文本.

    $' ... Includes all the text of the input string after the match in the replacement string.

    $+ ...在替换字符串中包括 最后个捕获的组. [这使您无需了解最后一组的特定索引.]

    $+ ... Includes the last group captured in the replacement string. [This relieves you of the need to know the last group's specific index.]

    $_ ...在替换字符串中包含整个 input 字符串.

    $_ ... Includes the entire input string in the replacement string.

    最后，请注意:

    • -replace始终匹配 global ，因此，如果输入字符串包含 multiple 个匹配项，则上述替换适用于 >每个匹配.

    • -replace invariably matches globally, so if the input string contains multiple matches, the replacements above apply to each match.

    对于正则表达式和替换字符串，通常最好使用'...'(单引号)，因为单引号字符串不是扩展(非插值)，因此避免与PowerShell自己的$前缀标记的前期扩展和`字符的解释混淆. 如果确实需要包含PowerShell变量，则有三个选项:

    It is generally preferable to use '...' (single quotes) for both the regex and the replacement string, because single-quoted strings are non-expanding (non-interpolating), and therefore avoid confusion with PowerShell's own up-front expansions of $-prefixed tokens and interpretation of ` chars.
    If you do need to include a PowerShell variable, you have three options:

    使用"..."(扩展字符串)和` -escape $实例，这些实例用于 regex引擎；例如，在以下示例中为`$1:
    'abc' -replace '(a)', "[`$1]-$HOME-"，产生类似[a]-C:\Users\jdoe-bc

    Use "..." (expanding strings) and `-escape $ instances that are meant for the regex engine; e.g., `$1 in the following example:
    'abc' -replace '(a)', "[`$1]-$HOME-", which yields something like [a]-C:\Users\jdoe-bc

    使用字符串连接(+)从文字片段和变量引用构建字符串；例如:
    'abc' -replace '(a)', ('[$1]-' + $HOME + '-')

    Build your string from literal pieces and variable references using string concatenation (+); e.g.:
    'abc' -replace '(a)', ('[$1]-' + $HOME + '-')

    使用-f(字符串格式运算符字符串串联)；例如:
    'abc' -replace '(a)', ('[$1]-{0}-' -f $HOME)

    Use -f, the string-formatting operator string concatenation; e.g.:
    'abc' -replace '(a)', ('[$1]-{0}-' -f $HOME)

    鉴于您需要使用$$在 replacement 字符串中转义文字$，请使用以下惯用法来使用字面意义的变量:

    Given that you need to use $$ to escape a literal $ in the replacement string, use the following idiom to use a variable whose value you want to use literally:

    • ... -replace <search>, $var.Replace('$', '$$')
    • 这取决于 [string]::Replace() 方法 执行文字子字符串替换.
      另外，在简单情况下，此方法是-replace的替代方法，但请注意，默认情况下，此方法区分大小写 .
    • 或者，使用嵌套的-replace调用，但是由于转义的要求，语法很棘手:
      ... -replace <search>, ($var -replace '\$', '$$$$')
    • ... -replace <search>, $var.Replace('$', '$$')
    • This relies on the [string]::Replace() method performing literal substring replacements.
      On a side note, this method is an alternative to -replace in simple cases, but note that it is case-sensitive by default.
    • Alternatively, use a nested -replace call, but the syntax is tricky due to the escaping requirements:
      ... -replace <search>, ($var -replace '\$', '$$$$')

    这篇关于通过重新格式化现有文件名来重命名文件-与-replace运算符一起使用的替换字符串中的占位符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！