Re^2: Save the resultant of " hash sorted by values "

Is that what you want? If it isn't, then you simply need to do a Schwartzian Transform

Using the Schwartzian Transform doesn't help at all. It's the generation of a comparable key that made the difference.

sub ip_to_key { sprintf "%03d", split /\./, $_[0] }

my @sortedKeys =
    sort { ip_to_key($ipaddr{$a}) cmp ip_to_key($ipaddr{$b}) }
    keys %ipaddr;
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The ST is an optimisation to get more speed out of it. If you really needed speed, this is much faster:

my @sortedKeys =
    map substr($_, 4),
    sort
    map pack('C4', split(/\./, $ipaddr{$_})) . $_,
    keys %ipaddr;
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Re^3: Save the resultant of " hash sorted by values "
by wind (Priest) on Mar 23, 2011 at 20:14 UTC

I feel your nitpicking, but fair enough. :) Yes, the point is that he's not sorting on the correct values (most likely) and he can certainly use a function to translate the keys just as well as using a ST. I personally would prefer to keep the code in one place given this is just an example though.

sub ip_to_key { join '', map {sprintf "%03d", $_} split /\./, $_[0] }
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Finally, thanks for sharing the pack method of doing a ST as it is definitely snazzier. I use it sometimes as well, but don't feel that it's as immediately decypherable by coders learning about sorts. Although, certainly the easiest method would probably be the functional translation sort {func($a) cmp func($b)}.

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Re^4: Save the resultant of " hash sorted by values "

by ikegami (Patriarch) on Mar 23, 2011 at 22:27 UTC

Yes, the point is that he's not sorting on the correct values (most likely) and he can certainly use a function to translate the keys just as well as using a ST.

No. You must use the function (or equivalent). Whether ST is used or not has no bearing on whether it works or not.

	With ST	Without ST
With function	Works	Works
Without function	Doesn't work	Doesn't works

As an aside, using ST doesn't only make the code more complex, I suspect it also makes the makes it slower in this case.

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Re^5: Save the resultant of " hash sorted by values "

by wind (Priest) on Mar 23, 2011 at 22:43 UTC

I feel you're reading more into my words than is there. If you'd like me to be more clear

Yes, the point is that he's not sorting on the correct values (most likely) and he can certainly use a function to translate the keys within the sort block just as well as using a ST to precache the correctly translated keys.

Didn't talk at all about what's a function and what isn't one. My main point is and was only that his sort order was probably not what he wanted. The means of fixing it is up to him, I just provided a single example.

Nevertheless, thanks again for sharing alternative methods.

Cheers

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