在PowerShell中如何让循环每1秒计数1次？

Question

我已经写了一段代码，从1数到20，5开始睡眠，然后继续。但是我需要计数器每秒计数1，所以整个循环需要25秒才能运行。现在只需要7-9秒。

$counter = 0
for ($counter -lt 20)
{
    Start-sleep 0
    $Counter++
    write-host $Counter
    if ($Counter -eq 10)
    {
        Start-sleep 5
    }
    If ($Counter -eq 20)
    {
        Break
    }
}

Answer 1

秒表可以用来更好地计时。一旦您达到阈值(10秒)，您必须重新启动它。

这种方法唯一的缺点是，如果你是在7秒，然后你在循环中做了一些事情，花了5秒，你将在12秒到达10秒循环(这就是为什么我使用-ge作为条件)。

$StopWatch = New-Object -TypeName 'System.Diagnostics.Stopwatch'
$StopWatch.Start()

For ($Counter = 0;$counter -lt 20) {
    Write-Host '.' -NoNewline
    Start-Sleep -Milliseconds 500 

    if ($StopWatch.Elapsed.Seconds -ge 10) {
        Write-Host ''
        Write-Host "$($StopWatch.Elapsed.Seconds) seconds elapsed... " -ForegroundColor Cyan
        $StopWatch.Restart()
    }

}

或者，您可以将您的主要内容放在一个作业中，这样即使需要2分钟才能完成，10秒循环仍将正确执行。

$MainStuffAction = {
   Start-Sleep -Seconds 20
    Write-Host 'Completed !'
}


$MainStuff = Start-Job -ScriptBlock $MainStuffAction 
$StopWatch = New-Object -TypeName 'System.Diagnostics.Stopwatch'
$StopWatch.Start()

while($true) {
    if ($StopWatch.Elapsed.Seconds -ge 10) {
        Write-Host '10 seconds elapsed!' 

        # We only restart the stopwatch at the end to get our full 10 seconds
        $StopWatch.Restart()
    } 
    elseif ($MainStuff.State -ne 'Running') {
        $MainStuff | Receive-Job
        $MainStuff = Start-Job -ScriptBlock $MainStuffAction 
    }

    Start-Sleep -Milliseconds 500

}

Answer 2

这是另一种方法。它使用while结构并显示$Counter和$Stopwatch的值，因此您可以清楚地看到它是否正在执行您想要的操作。笑一笑

$Stopwatch = [System.Diagnostics.Stopwatch]::new()
$Stopwatch.Start()

$Counter = 0
# correct for off-by-one
$Threshold = 19
while ($Counter -le $Threshold)
    {
    Start-Sleep -Seconds 1
    $Counter ++
    'Counter = {0:D2}, Seconds = {1:D2}' -f $Counter, $Stopwatch.Elapsed.Seconds
    if ($Counter -eq 10)
        {
        Start-Sleep -Seconds 5
        '{0} {1:D2} Seconds' -f (' ' * 15), $Stopwatch.Elapsed.Seconds
        }
    }

$Stopwatch.Stop()
$Stopwatch.Elapsed.TotalSeconds

输出...

Counter = 01, Seconds = 01
Counter = 02, Seconds = 02
Counter = 03, Seconds = 03
Counter = 04, Seconds = 04
Counter = 05, Seconds = 05
Counter = 06, Seconds = 06
Counter = 07, Seconds = 07
Counter = 08, Seconds = 08
Counter = 09, Seconds = 09
Counter = 10, Seconds = 10
                15 Seconds
Counter = 11, Seconds = 16
Counter = 12, Seconds = 17
Counter = 13, Seconds = 18
Counter = 14, Seconds = 19
Counter = 15, Seconds = 20
Counter = 16, Seconds = 21
Counter = 17, Seconds = 22
Counter = 18, Seconds = 23
Counter = 19, Seconds = 24
Counter = 20, Seconds = 25
25.2769325