字符串比较在PowerShell函数中不起作用 - 我做错了什么？ [英] String comparison not working in PowerShell function - what am I doing wrong?

问题描述

我正在尝试制作 git commit 的别名，该别名也会将邮件记录到单独的文本文件中。但是，如果 git commit 返回没有提交（工作目录干净），它不应该记录任何东西到单独的文件。

这是我的代码。 git commit 别名有效;输出到文件的作品。但是，无论从 git commit 中返回的内容如何，​​它都会记录消息。

  git-commit-and-log（$ msg）
 {
 $ q = git commit -a -m $ msg 
 $ q 
 if（$ q  - notcontainsnothing to commit）{
 $ msg | Out-File w：\ log.txt -Append 
} 
} 
 
 Set-Alias -Name gcomm -Value git-commit-and-log 
  

我使用的是PowerShell 3.

解决方案

$ q 包含每行Git stdout的字符串数组。要使用 -notcontains ，您需要匹配数组中一个项目的完整字符串，例如：

<$

$ q -notcontains没有提交，工作目录干净 p>如果要测试部分字符串匹配，请尝试 -match 运算符。 （注意 - 它使用正则表达式并返回匹配的字符串。）

  $ q -matchnothing to commit
  

-match 如果左操作数是数组。所以你可以使用这个逻辑：



  if（-not（$ q -matchnothing to commit））{
有东西要提交..
} 
  

另一个选择是使用 -like / -notlike 运算符。这些接受通配符并且不使用正则表达式。匹配（或不匹配）的数组项将被返回。所以你也可以使用这个逻辑：



  if（-not（$ q -likenothing to commit *））{ 
有东西要提交..
} 
  




I'm trying to make an alias of git commit which also logs the message into a separate text file. However, if git commit returns "nothing to commit (working directory clean)", it should NOT log anything to the separate file.

Here's my code. The git commit alias works; the output to file works. However, it logs the message no matter what gets returned out of git commit.

function git-commit-and-log($msg)
{
    $q = git commit -a -m $msg
    $q
    if ($q –notcontains "nothing to commit") {
        $msg | Out-File w:\log.txt -Append
    }
}

Set-Alias -Name gcomm -Value git-commit-and-log

I'm using PowerShell 3.

解决方案

$q contains a string array of each line of Git's stdout. To use -notcontains you'll need to match the full string of a item in the array, for example:

$q -notcontains "nothing to commit, working directory clean"

If you want to test for a partial string match try the -match operator. (Note - it uses regular expressions and returns a the string that matched.)

$q -match "nothing to commit"

-match will work if the left operand is an array. So you could use this logic:

if (-not ($q -match "nothing to commit")) {
    "there was something to commit.."
}

Yet another option is to use the -like/-notlike operators. These accept wildcards and do not use regular expressions. The array item that matches (or doesn't match) will be returned. So you could also use this logic:

if (-not ($q -like "nothing to commit*")) {
    "there was something to commit.."
}

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