How to sort string array first by letter then by number combination?

Question

I can't figure out how to sort a string array first by letter then by number combination. Here is the sample:

$a = @('aa101','aa11','ab10','ab9','a111','a22','a01')

I would like to see the result after the sorting as follow:

a01
a22
a111
aa11
aa101
ab9
ab10

Please help me to find out the answer by using PowerShell script.

The sorting algorithm you describe (sort by first letter, then number), would yield a different result than your example — Mathias R. Jessen
– Mathias R. Jessen, Commented Dec 31, 2016 at 12:06
Hi, Mathias, what would be the result, could please explain? — Liang Cui
– Liang Cui, Commented Dec 31, 2016 at 12:09
Sorting these values by first letter has no effect on the set you've described (they all start with a), sorting by numbers you would get a01 first (01 is 1, the smallest number in the set), then ab9 (9 is the second-smallest), then ab10 etc. — Mathias R. Jessen
– Mathias R. Jessen, Commented Dec 31, 2016 at 12:11

Mathias R. Jessen · Accepted Answer · 2016-12-31 12:14:32Z

4

The Sort-Object cmdlet can take one or more scriptblocks as its Property argument. First argument should remove all the digits at the end, then remove all non-digits and cast to an integer:

$a |Sort-Object {"$_" -replace '\d',''},{("$_" -replace '\D','') -as [int]}

\d is regex for digits
\D is regex for anything that isn't digits

answered Dec 31, 2016 at 12:14

Mathias R. Jessen

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3 Comments

Liang Cui Over a year ago

YES! Thank you so much, Mathias! I didn't realize the sort-object can take two expressions separated by comma. I refined just a little bit to save some typing. $a | Sort-Object {"$_" -replace '\d'},{[int]("$_" -replace '\D')}

Mathias R. Jessen Over a year ago

@LiangCui You can also combine expressions and property names if need be: $a |Sort-Object Length,{[int]("$_"-replace'\D','')}

Liang Cui Over a year ago

uh... got it. I am so new to stackoverflow. My bad for the inconvenience.

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