windows 字符串比较在 PowerShell 函数中不起作用 - 我做错了什么？
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String comparison not working in PowerShell function - what am I doing wrong?
提问by adrienne
I'm trying to make an alias of git commitwhich also logs the message into a separate text file. However, if git commitreturns "nothing to commit (working directory clean)", it should NOT log anything to the separate file.
我正在尝试创建一个别名，git commit它也将消息记录到一个单独的文本文件中。但是，如果git commit返回"nothing to commit (working directory clean)"，则不应将任何内容记录到单独的文件中。
Here's my code. The git commitalias works; the output to file works. However, it logs the message no matter what gets returned out of git commit.
这是我的代码。该git commit别名作品; 输出到文件有效。但是，无论从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.
我正在使用 PowerShell 3。
回答by Andy Arismendi
$qcontains a string array of each line of Git's stdout. To use -notcontainsyou'll need to match the full string of a item in the array, for example:
$q包含 Git 标准输出的每一行的字符串数组。要使用，-notcontains您需要匹配数组中项目的完整字符串，例如：
$q -notcontains "nothing to commit, working directory clean"
If you want to test for a partial string match try the -matchoperator. (Note - it uses regular expressions and returns a the string that matched.)
如果要测试部分字符串匹配，请尝试使用-match运算符。（注意 - 它使用正则表达式并返回匹配的字符串。）
$q -match "nothing to commit"
-matchwill work if the left operand is an array. So you could use this logic:
-match如果左操作数是一个数组，它将起作用。所以你可以使用这个逻辑：
if (-not ($q -match "nothing to commit")) {
"there was something to commit.."
}
Yet another option is to use the -like/-notlikeoperators. 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:
另一种选择是使用-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 -like "nothing to commit*")) {
"there was something to commit.."
}
回答by Bill_Stewart
Just a note that the -notcontainsoperator doesn't mean "string doesn't contain a substring." It means "collection/array doesn't contain an item." If the "git commit" command returns a single string, you might try something like this:
请注意-notcontains运算符并不意味着“字符串不包含子字符串”。这意味着“集合/数组不包含项目”。如果“git commit”命令返回单个字符串，您可以尝试以下操作：
if ( -not $q.Contains("nothing to commit") )
I.e., use the Containsmethod of the String object, which does return $true if a string contains a substring.
即，使用String 对象的Contains方法，如果字符串包含子字符串，它会返回 $true。
