Question

使用-Match会为我提供True / False个值，而不是文本行。

Get-Content ("\\path”) -tail 10 -wait | % {
    foreach ($data in ($_ -match "Execute")) {
        $First = $data.Substring(26,37).Trim()
        Write-Host $First
    }
}

我使用下面没有-tail -wait的代码来执行我的操作，但我无法使用-tail Get-Content更改为解析文件。

$DB = Get-Content ("\\path”) -tail -ReadCount 5000000  | foreach { $_ -match "string to match" } | foreach{ $_.Trim()}  

foreach ($Data in $DB) {
    $First = $Data.Substring(26,37).Trim()
    $Second = $Data
    Write-Host $First
    Write-Host $Second
}

Answer 1

As a workaround, you can array-cast your $_, like this:

foreach ($data in (,$_ -match "Execute")) {

Here's the output difference:

$data=@("bla bla","foo bla","foo bar","bla bar")
PS > $data | % { foreach ($a in ($_ -match "bla")){$a}}
True
True
False
True
PS > $data | % { foreach ($a in (,$_ -match "bla")){$a}}
bla bla
foo bla
bla bar

Answer 2

嗯，db.driver = org.h2.Driver db.url = jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;INIT=RUNSCRIPT FROM \'classpath:create-db.sql\' db.username = cost db.password = cost entitymanager.packages.to.scan = com.somecompany.cost hibernate.dialect = org.hibernate.dialect.H2Dialect hibernate.show_sql = false hibernate.format_sql = false应用于标量时返回一个布尔结果。应用于数组时，它返回匹配的元素。在第二个示例中，您使用-match强制ReadCount一次通过管道发送多行。当然，您每次都会获得一行数而不仅仅是一行，从而改变了Get-Content的语义。

要使您的第一个示例正常工作，只需将-match更改为foreach。

Answer 3

-match表达式返回布尔结果，但也更新特殊变量$matches。

您可以使用-match表达式中的where-object来过滤行，只返回匹配的行。

$myFilteredArray = $myArray | where-object{$_ -match 'execute'}

如果将它用于简单的事情，你也可以使用-like：

$myFilteredArray = $myArray | where-object{$_ -like '*execute*'}

如果你想要聪明，你也可以使用正则表达式;那样$matches将保存所有捕获的组（包括一个名为0的特殊组，其中包含原始行。）

简单示例/纯文本搜索

@(
    'line 1 - please '
    ,'line 2 - execute'
    ,'line 3 - this'
    ,'line 4 - script'
) | where-object {$_ -match 'execute'} | foreach-object{
    "-Match found the following matches:"
    $matches
    "The line giving this result was"
    $_
}

使用正则表达式/捕获组的示例

@(
    'line 1 - please '
    ,'line 2 - execute'
    ,'line 3 - this'
    ,'line 4 - script'
) | where-object {$_ -match '(?<capturedData>.*?)(?: - )execute'} | foreach-object{
    "-Match found the following matches:"
    $matches
    "The line giving this result was"
    $_
}

-match：https://ss64.com/ps/syntax-regex.html
-like，-match以及其他比较：https://ss64.com/ps/syntax-compare.html

Get-Content with Wait并处理每一行

3 个答案: