Sort using rDNS naming

bgstack15 — Thu, 23 Jan 2025 14:23:00 GMT

Notice

This post has nothing to do with dns or reverse dns. This is only talking about sorting text.

Main

Sort of like how flippin' freedesktop.org uses "reverse DNS names" to get such lovely files as /usr/share/applications/org.geeqie.Geeqie.desktop, I wanted to sort some domain names. A sorted list looks less like I just made it up, and like I pulled it out of a report or tool!

So I have a small script here that sorts via "reverse DNS" convention.

awk -F'.' '
{
    for (i=NF; i>0; i--) {
        printf "%s %s", $(i), (i>1 ? "." : "")
    }
    print $0
}' | sort | awk '{print $NF}'

It was too small to bother putting it in the files/ for this post.

Updated 2026-02-17 I would name this script `rdns-sort`.

Python natural sort by object attribute

bgstack15 — Wed, 02 Mar 2022 14:22:03 GMT

I wanted to sort a list of custom classes in Python. I wanted to sort the list by the .albumid attribute of the objects. A natural sort is where the order is 1-9, 10-19, 20-29, etc., instead of 1, 10-19, 2, 20-29, 3, 30-39, etc. It is very useful for when you want to sort a string that nominally has numbers at the beginning.

def natural_sort(l, attrib):
    convert = lambda text: int(text) if text.isdigit() else text.lower()
    alphanum_key = lambda key: [convert(c) for c in re.split('([0-9]+)', key.__dict__[attrib])]
    return sorted(l, key=alphanum_key)

results = natural_sort(albums, 'albumid')

I posted this insight on Stackoverflow.

Knowledge Base (Posts about sort)

Sort using rDNS naming

Notice

Main

Updated 2026-02-17 I would name this script rdns-sort.

Python natural sort by object attribute

Updated 2026-02-17 I would name this script `rdns-sort`.