Array Slicing - Powershell compared to Python

Hi,

I guess this is a question for the Powershell team.

When comparing array slicing with for example Python, I find that Powershell
does not support doing what i most often use slicing for, ie "Get all but
the first/last n items".

In python you can write
somelist[:-3]
to get all but the last three (and the empty list if there are less than
three elements in the list)

In powershell you have to write:

if ($somelist.Length -gt 3){
@()
}
else {
$somelist[0..($somelist.Length -4)]
}

I would be quite hard pressed to call the Powershell way more elegant. Are
there any plans for vNext to improve this area?

Regards,
/Staffan

Howdy Staffan!
I have 2 thoughts on this:
1) We have a really big list of amazing features we'd like to get
implemented in Vnext and are in the process of deciding which ones we won't
do (to ship is to choose). This doesn't "pop" as a compelling feature to
me.

2) We are very customer driven. The fact that you've asked about it means a
lot. Please submit this as a request via Connect and then other people can
vote on it. We don't have the bandwidth to implement all feature requests
but we do have bandwidth to implement some of the ones that the community
asks for the most.

Thanks for asking!
--
Jeffrey Snover [MSFT]
Windows Management Partner Architect
Microsoft Corporation
This posting is provided "AS IS" with no warranties, no confers rights.
Visit the Windows PowerShell Team blog at:
http://blogs.msdn.com/PowerShell
Visit the Windows PowerShell ScriptCenter at:
http://www.microsoft.com/technet/scr.../hubs/msh.mspx

You could do this with type extensions (I posted about this example on
my blog here: http://www.aaronlerch.com/blog/2007/...xtensions.html)

In this case, something like this should work:

<Types>
<Type>
<Name>System.Array</Name>
<Members>
<ScriptMethod>
<Name>Slice</Name>
<Script>
if ($args[0] -eq $null) { $start = 0 }
elseif ($args[0] -lt 0) { $start = $this.Length + [int]$args[0] }
elseif ($args[0] -ge 0) { $start = [int]$args[0] }

if ($args[1] -eq $null) { $end = $this.Length - 1 }
elseif ($args[1] -lt 0) { $end = $this.Length + [int]$args[1] -
1 }
elseif ($args[1] -ge 0) { $end = [int]$args[1] - 1 }

if ($start -lt 0) { $start = 0 }
elseif ($start -gt $this.Length) { return @() }

if ($end -gt $this.Length) { $end = $this.Length }
elseif ($end -lt 0) { return @() }

if ($start -ge $end) { return @() }
else { return $this[$start..$end] }
</Script>
</ScriptMethod>
</Members>
</Type>
</Types>

On May 5, 12:11 pm, "Jeffrey Snover [MSFT]" <jsno...@microsoft.com>
wrote:
> Howdy Staffan!
> I have 2 thoughts on this:
> 1) We have a really big list of amazing features we'd like to get
> implemented in Vnext and are in the process of deciding which ones we won't
> do (to ship is to choose). This doesn't "pop" as a compelling feature to
> me.
>
> 2) We are very customer driven. The fact that you've asked about it means a
> lot. Please submit this as a request via Connect and then other people can
> vote on it. We don't have the bandwidth to implement all feature requests
> but we do have bandwidth to implement some of the ones that the community
> asks for the most.
>
> Thanks for asking!
> --
> Jeffrey Snover [MSFT]
> Windows Management Partner Architect
> Microsoft Corporation
> This posting is provided "AS IS" with no warranties, no confers rights.
> Visit the Windows PowerShell Team blog at:http://blogs.msdn.com/PowerShell
> Visit the Windows PowerShell ScriptCenter at:http://www.microsoft.com/technet/scr.../hubs/msh.mspx