Get all directories in directory that has a numeric name with powershell - powershell

Question

I will start off by saying I am new to powershell...
I can get all the directories in a specified directory but I need to only get the directories that their names are numeric. Example:
1 - include
2 - include
3 - include
10 - include
LastFailed - exclude
I also will need to order them in sequential order for later processing.
Here is what I have so far:
$Dirs = Get-ChildItem -Path ..\..\..\builds -Attributes D
foreach($D in $Dirs)
{
Write-Host $D.Name
}

Answer 1

To get a list of just the folders that have numeric names, you can do this:
$Path = '..\..\..\builds'
$Dirs = Get-ChildItem -Path $Path -Attributes D |
Where-Object { $_.Name -match '^\d+$' } |
Sort-Object
$Dirs
This code above uses the Where-Object clause to filter out only the folders that have a numeric-only name.
It does this by using the -match operator and the regular expression ^\d+$ where:
`^` --> start at the beginning of the line
`\d` --> look for numeric values (0-9)
`+` --> there must be 1 or more numeric values present
`$` --> the end of the string
Instead of \d it could also have been written using [0-9]
The code ends with Sort-Object because the OP wants the list of folders sorted.
because we do not tell what property to sort on here, Powershell defaults to the Name.
The above will produce a list like:
Mode LastWriteTime Length Name
---- ------------- ------ ----
d----- 18-8-2018 16:13 1
d----- 18-8-2018 16:13 10
d----- 18-8-2018 16:13 2
d----- 18-8-2018 16:13 5
As you can see, the list is sorted by property Name, but.. the numbers were treated as strings, so '10' follows '1'.
What we most likely want to do here is to have the Sort-Object treat the names as real Numbers, not strings.
To fix that we add the Select-Object cmdlet in order to create our own objects with properties we need.
We can get standard properties of the DirInfo object that is coming through the pipeline, AND it is possible to create a new calculated property.
Here I add the calculated property called SortIndex that is simply the numeric value converted from the Name, which we will then use for the numeric sort:
$Dirs = Get-ChildItem -Path $Path -Attributes D |
Where-Object { $_.Name -match '^\d+$' } |
Select-Object -Property FullName, Name, LastWriteTime, #{Name = 'SortIndex'; Expression = {[int]$_.Name} } |
Sort-Object -Property SortIndex
$Dirs
Now it produces an array of objects that when printed to console looks like this:
FullName Name LastWriteTime SortIndex
-------- ---- ------------- ---------
D:\Temp\1 1 18-8-2018 16:13:22 1
D:\Temp\2 2 18-8-2018 16:13:25 2
D:\Temp\5 5 18-8-2018 16:13:28 5
D:\Temp\10 10 18-8-2018 16:13:31 10
Hope this helps.

Answer 2

You can utilize Where-Object to filter your collection:
$dirs = Get-ChildItem -Path ..\..\..\builds -Directory |
Where-Object -Property Name -Match '\d'
This operation uses regex to match the digit class.
If you meant you only want the directory names that start with a digit, you can use an anchor:
'^\d'
and lastly, you can sort them with Sort-Object:
$dirs = Get-ChildItem -Path ..\..\..\builds -Directory |
Where-Object -Property Name -Match '^\d' |
Sort-Object -Property Name
You can further enhance this sort by being explicit about the starting digit:
-Property {[int]($_.Name -split '[^\d]')[0]}
In this context, we're splitting on the first non-digit character and capturing the first fragment that was split off (which should be the number represented as a string, so we cast to an integer).