Convert seconds to hh:mm:ss,fff format in PowerShell

In PowerShell 4.0

$s = "7000.6789"
$ts =  [timespan]::fromseconds($s)
("{0:hh\:mm\:ss\,fff}" -f $ts)

Output: 01:56:40,679

---

In PowerShell 2.0

$s = "7000.6789"
$ts =  [timespan]::fromseconds($s)
"{0:hh:mm:ss,fff}" -f ([datetime]$ts.Ticks)

Output: 01:56:40,679

---

And to go back the other way...

$text = "01:56:40,679"
$textReformat = $text -replace ",","."
$seconds = ([TimeSpan]::Parse($textReformat)).TotalSeconds
$seconds

Output: 7000.679

You could just use the ToString method on the TimeSpan object and specify the format you want to use. Either use one of the standard timespan formats or use a custom timespan format. For example, the following custom format gives the output you want:

$ts =  [timespan]::fromseconds("7000.6789")
$ts.ToString("hh\:mm\:ss\,fff")

This will output

01:56:40,679

Update: Updating to provide functions working in PowerShell v2

The above solution works well in PowerShell v4, but not in v2 (since the TimeSpan.ToString(string) method wasn't added until .NET Framework 4).

In v2 I guess you'll have to either create the string manually (like you are doing in the question) or doing an ordinary ToString() and manipulate the string. I suggest the former. Here's a function which works fine for that:

function Format-TimeSpan
{
    PARAM (
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [TimeSpan]$TimeSpan
    )

    #Current implementation doesn't handle days.

    #By including the delimiters in the formatting string it's easier when we contatenate in the end
    $hours = $TimeSpan.Hours.ToString("00")
    $minutes = $TimeSpan.Minutes.ToString("\:00")
    $seconds = $TimeSpan.Seconds.ToString("\:00")
    $milliseconds = $TimeSpan.Milliseconds.ToString("\,000")

    Write-Output ($hours + $minutes + $seconds + $milliseconds)
}

Testing it using

$ts =  [timespan]::fromseconds("7000.6789")

Format-TimeSpan -TimeSpan $ts
$ts | Format-TimeSpan

Yields the following output:

01:56:40,679
01:56:40,679

One line conversion :

[timespan]::fromseconds(354801857.86437).tostring()

return 4106.12:04:17.8640000