PowerShell doesn't seem to sort objects by name ascending correctly:
dir | Sort-Object Name
My goal is to sort the elements in this order:
1.sql
2.sql
3.sql
...
9.sql
10.sql
11.sql
...
Is there a way to solve this?
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sɐunıɔןɐqɐp
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Francesco Mantovani
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Per default `dir` is sorted by name. – Timo Mar 07 '21 at 19:38
2 Answers
7
You need to sort the filenames as numbers, rather than as text. It's convenient because the filenames in your example are entirely numbers, so you can change the sort to use a dynamic scriptblock property, which will evaluate the filename to a number for each item in the pipeline:
| sort-object -Property {
if (($i = $_.BaseName -as [int])) { $i } else { $_ }
}
That means: if the filename can be converted to an integer, then use that, otherwise use it as it is.
sɐunıɔןɐqɐp
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TessellatingHeckler
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I want to sort `Get-Item env:|sort -Property name`, but it sorts similar to just `get-item env:`. Is this a new question or can you answer here? – Timo Mar 07 '21 at 19:42
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1@Timo I think the difference is between `Get-Item env:` and `Get-ChildItem env:`, the first returns a single ValueCollection, the second returns an array of entries. I'm not sure on the details, but `Env:` is a PowerShell Provider pretending to be a drive like `C:`, so it's like doing `Get-Item C:` and expecting to get all the files inside. You can do it with `Get-ChildItem Env: | Sort-Object -Property Name` or something like `(Get-Item Env:).GetEnumerator() | Sort-Object -Property Name`. – TessellatingHeckler Mar 10 '21 at 23:58
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get-childitem put me on the right track. Why is `(Get-Item c:).GetEnumerator()` not working? (IT is like one question leads to another;)) Probably because get-item c: returns one object, so there is no enumerator. Anyway, just `gci env:` works – Timo Mar 12 '21 at 19:26
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1@Timo I'm guessing a lot: `Get-Item C:` is type `System.IO.DirectoryInfo`, the same as any directory, which goes back to early .Net and C#. `Env:` is PowerShell only, it's not a filesystem directory so must be another type, and what they used (ValueCollection) has an enumerator. I guess DirectoryInfo doesn't have one because it's more complex than "contents" only - see `(get-item c:\)|gm enumerate*, get*` and there are methods to enumerate Files, Directories, both, overloads for with/without subdirectories, Access control lists, etc. Too much for one enumerator. – TessellatingHeckler Mar 12 '21 at 21:17
1
For more complex patterns enclosed in alphabetic characters use $ToNatural which expands all embedded numbers to a unique length (here 20) by left padding with zeros.
Source: Roman Kuzmin - How to sort by file name the same way Windows Explorer does?
$ToNatural = { [regex]::Replace($_, '\d+', { $args[0].Value.PadLeft(20,"0") }) }
Generate some test data:
> (10..11 + 100..101 + 1..2)|%{new-item -itemtype file -path ("pre_{0}_post.sql" -f $_)
Directory: A:\
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 2018-07-27 11:02 0 pre_10_post.sql
-a---- 2018-07-27 11:02 0 pre_11_post.sql
-a---- 2018-07-27 11:02 0 pre_100_post.sql
-a---- 2018-07-27 11:02 0 pre_101_post.sql
-a---- 2018-07-27 11:02 0 pre_1_post.sql
-a---- 2018-07-27 11:02 0 pre_2_post.sql
> dir| sort
Directory(: A:\
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 2018-07-27 11:02 0 pre_1_post.sql
-a---- 2018-07-27 11:02 0 pre_10_post.sql
-a---- 2018-07-27 11:02 0 pre_100_post.sql
-a---- 2018-07-27 11:02 0 pre_101_post.sql
-a---- 2018-07-27 11:02 0 pre_11_post.sql
-a---- 2018-07-27 11:02 0 pre_2_post.sql
> dir|sort $ToNatural
Directory: A:\
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 2018-07-27 11:02 0 pre_1_post.sql
-a---- 2018-07-27 11:02 0 pre_2_post.sql
-a---- 2018-07-27 11:02 0 pre_10_post.sql
-a---- 2018-07-27 11:02 0 pre_11_post.sql
-a---- 2018-07-27 11:02 0 pre_100_post.sql
-a---- 2018-07-27 11:02 0 pre_101_post.sql
sɐunıɔןɐqɐp
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