How to work with regular expressions

Hi!

When I do:


dir | where { $_.Name -match "\d+" }

It displays names containing numbers.
What if I want to have just those matched numbers?

So if the file name is : powerShell_01.txt
I want to have this 01 how to get this?

Later on I'd like to convert it to a number so if it's
0001 or 001 or 000001 it's just 1.

and rename files

Thx for help with this.

Jedrzej

Jarod wrote: As Shay posted in an earlier thread:
http://safari.oreilly.com/9780596528...sion_reference

Is definitely a good reference!

--
Microsoft MVP - Windows PowerShell
http://www.microsoft.com/mvp

PowerGadgets MVP
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Blog:
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"Jarod" <Jarod@xxxxxx> wrote in message
news:0FC1C754-9CAE-4F4F-A4F0-F83EE1564E09@xxxxxx dir | %{if ($_.name -match '(\d+)') { $matches[1] }}

Any match with the operator -match updates a global called $matches. Any
capture groups (named or unnamed) are created as properties on this object.
$matches[1] would be the first unnamed capture group.

--
Keith

> What if I want to have just those matched numbers?

You can access what's been matched by your entire pattern with $matches[0]
I spent ages trying to figure out how to do this. It seemed odd to me that
you can conver a number to a string using .tostring but can't convert a
string to a number using .tonumber (no such thing). Instead, do this:

$i = "00001"
$numeric_i = [int] $i

Mike

"Jarod" <Jarod@xxxxxx> wrote in message
news:0FC1C754-9CAE-4F4F-A4F0-F83EE1564E09@xxxxxx

## create test files

1..9 | foreach {new-item -path ".\powershell_0$_.txt" -itemtype file -force}

Mode LastWriteTime Length Name
---- ------------- ------ ----
-a--- 17/12/2007 21:22:03 0.0 B powershell_01.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_02.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_03.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_04.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_05.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_06.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_07.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_08.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_09.txt



## get all files and rename
dir powershell_*.* | foreach {
[int]$num = ([regex]'\d+').match($_.name).value
rename-item $_.name "powershell_$num.txt" -force
}


dir powershell_*.*

Mode LastWriteTime Length Name
---- ------------- ------ ----
-a--- 17/12/2007 21:22:03 0.0 B powershell_1.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_2.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_3.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_4.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_5.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_6.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_7.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_8.txt
-a--- 17/12/2007 21:22:03 0.0 B powershell_9.txt



-----
Shay Levi
$cript Fanatic
http://scriptolog.blogspot.com
Hebrew weblog: http://blogs.microsoft.co.il/blogs/scriptfanatic

> > What if I want to have just those matched numbers? How can i find such things in manual ? It looks like old good .net type
casting But in .net at least in c# you use (int) not [int].. It would be
better if they left this like it was

Jedrzej