使用 PowerShell 替换部分字符串 [英] Partial String Replacement using PowerShell

问题描述

问题

我正在编写一个让用户提供特定 IP 地址的脚本，我想以某种方式屏蔽此 IP，以便它不会存储在日志中.我的问题是，当我知道 IP 的前三个值通常是什么时，我可以轻松地做到这一点；但是，如果可能的话，我想避免将这些值存储/硬编码到代码中.即使我不知道前三个值，我也希望能够替换这些值.

示例:

10.11.12.50 将显示为 XX.XX.XX.5010.12.11.23 也会显示为 XX.XX.XX.23

我已经查找了部分字符串替换，但我发现的问题或问题都没有接近于这样做.我试过做这样的事情:

# 这最终替换了所有数字$tempString = $str -replace '[0-9]', 'X'

我知道我已经到了一半，但我的目标是只替换前 3 组数字，所以基本上是."之前的每个数字，但我一直没能做到这一点.

>

问题

我正在尝试使用 PowerShell 可以实现吗?是否有实现这一目标的最佳实践方法?

解决方案

TheIncorrigible1 的有用答案 是一种准确的解决方法问题(仅当 3 个连续的 . 分隔的 1-3 位数字组匹配时才会发生替换.)

一个更宽松但更短的解决方案，它取代了最后一个 .-前缀的数字组:

PS>'10.11.12.50' -replace '.+(?=\.\d+$)', 'XX.XX.XX'XX.XX.XX.50

(?=\.\d+$) 是(正)先行断言 ((?=...)) 匹配封闭的子表达式(文字 . 后跟 1或更多数字 (\d) 在字符串的末尾 ($))，但不会将它捕获作为整体的一部分匹配.

最终效果是，只有 .+ 捕获的内容 - 前瞻断言匹配 之前 的所有内容 - 被替换为 'XX.XX.XX'.

应用于上述示例输入字符串，10.11.12.50:

• (?=\.\d+$) 匹配以 . 结尾的数字组，.50.

• .+ 匹配所有before .50，也就是10.11.12.

• 由于 (?=...) 部分未被捕获，因此它不包含在 replaced 中，因此它只是子字符串10.11.12 被替换，即使用 XX.XX.XX，结果产生 XX.XX.XX.50.>

Problem

I am working on a script that has a user provide a specific IP address and I want to mask this IP in some fashion so that it isn't stored in the logs. My problem is, that I can easily do this when I know what the first three values of the IP typically are; however, I want to avoid storing/hard coding those values into the code to if at all possible. I also want to be able to replace the values even if the first three are unknown to me.

Examples:

10.11.12.50 would display as XX.XX.XX.50
10.12.11.23 would also display as XX.XX.XX.23

I have looked up partial string replacements, but none of the questions or problems that I found came close to doing this. I have tried doing things like:

# This ended up replacing all of the numbers
$tempString = $str -replace '[0-9]', 'X'

I know that I am partway there, but I aiming to only replace only the first 3 sets of digits so, basically every digit that is before a '.', but I haven't been able to achieve this.

Question

Is what I'm trying to do possible to achieve with PowerShell? Is there a best practice way of achieving this?

解决方案

TheIncorrigible1's helpful answer is an exact way of solving the problem (replacement only happens if 3 consecutive .-separated groups of 1-3 digits are matched.)

A looser, but shorter solution that replaces everything but the last .-prefixed digit group:

PS> '10.11.12.50' -replace '.+(?=\.\d+$)', 'XX.XX.XX'
XX.XX.XX.50

(?=\.\d+$) is a (positive) lookahead assertion ((?=...)) that matches the enclosed subexpression (a literal . followed by 1 or more digits (\d) at the end of the string ($)), but doesn't capture it as part of the overall match.

The net effect is that only what .+ captured - everything before the lookahead assertion's match - is replaced with 'XX.XX.XX'.

Applied to the above example input string, 10.11.12.50:

• (?=\.\d+$) matches the .-prefixed digit group at the end, .50.

• .+ matches everything before .50, which is 10.11.12.

• Since the (?=...) part isn't captured, it is therefore not included in what is replaced, so it is only substring 10.11.12 that is replaced, namely with XX.XX.XX, yielding XX.XX.XX.50 as a result.

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