The story: A few obfus ago I had a bunch of lines that I wanted to randomize to keep the obfu from being deconstructed a little too quickly. So, I came up with a short script that I have since shortened to a one-liner:
123456789_123456789_123456789_123456789_123456789_123456789_1
perl -e'@l=<>;while(@l){$i=rand@l;print$l[$i];splice@l,$i,1}'
Scored in accordance with PGA Golf Rules, it hits the clubhouse at 61 chars. However, I'm sure there's probably much shorter ways out there that my feeble, cheese-filled mind isn't thinking of, and I figured some of you might get a little enjoyment out of this, so here we go...
Sample input:
This
is
some sample
input that
CheeseLord
put here
for you.
Sample output:
input that
for you.
put here
CheeseLord
is
some sample
This
Final Note: The space between -e and ' has proven optional everywhere I've tried it -- but if it turns out not to be somewhere, I'll gladly take the one-stroke penalty.
His Royal Cheeziness |
Re: (GOLF) Randomizing lines
by tadman (Prior) on Jul 26, 2001 at 17:39 UTC
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Err, 48 if you count the whole works:
perl -e'@l=<>;print while($_=splice@l,rand@l,1)'
</CODE>
Update:
Best beat myself before someone else does. As often occurs,
map inspires and produces useful results. 46 characters:
perl -e'map{splice@l,rand@l+1,0,$_}<>;print@l'
Or, if you really want to get down to brass tacks, 45 characters:
perl -e'splice@l,rand@l+1,0,$_ for<>;print@l'
Note that the '+1' can be eliminated if there is a blank
line at the start of the file.
Update 2.0
It occured to me to break sort and make it act all screwy,
which sure jumbles up the text a fair bit, for all intents
appearing totally random.
31 characters:
perl -e'print sort{4-rand 9}<>'
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Version 2, aside from the obvious defect of needing to be
adjusted to your file, is rather dangerous. It can dump
core on older Perls, and will be biased even on recent ones.
(I think you knew that, but I though it worth pointing out.)
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I'm not sure what you mean by "adjusted to your file", as
it seems to work quite well on any given data. It isn't
perfectly random, as things aren't shuffled quite as much
as the splice approach, but they are shuffled to the point
of being random-looking with no obvious patterns. Since
we're not picking winning lottery numbers, I thought that
would be acceptable.
I can only presume that since the output of the comparator used by
sort does return different values for the same $a-$b pair,
this could really bust a gasket on some of the older
Perls which perhaps assume that this would not occur. IMHO,
this is a bug in Perl more than it is a bug in the program,
as no program is supposed to be able to dump core, unless,
perhaps, it uses the dump command.
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Re: (GOLF) Randomizing lines
by jmcnamara (Monsignor) on Jul 26, 2001 at 17:54 UTC
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This will always randomise in the same way, which probably isn't what you want. Also, some lines might be lost if the file contains duplicate lines. However it is short.
22 chars:
perl -e'%_=<>;print%_' file
John.
--
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Then why not:perl -e'print%{{<>}}'
? (21 chars )
(and it's pretty), (and, as with the other, it even gets rid of duplicate odd-numbered lines (and the following line) for you.)
p
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Re (tilly) 1: (GOLF) Randomizing lines
by tilly (Archbishop) on Jul 26, 2001 at 17:47 UTC
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45 (oops, didn't score according to the
rules the first time, thanks CheeseLord) after some usual
compression.
123456789 123456789 123456789 123456789 12345
perl -e'@l=<>;print splice@l,rand@l,1while@l'
UPDATE
Does anyone have any ideas why I get a segmentation
fault from the following?
perl -e'print splice@l,rand@l,1for@l=<>'
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perl -e'print splice@l,rand@l,1for@m=@l=<>' t.txt
MeowChow
s aamecha.s a..a\u$&owag.print | [reply]
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That's really odd. I tried running it in the debugger:
$ perl -d -e'print splice@l,rand@l,1for@l=<>' < test
Default die handler restored.
Loading DB routines from perl5db.pl version 1.07
Editor support available.
Enter h or `h h' for help, or `man perldebug' for more help.
main::(-e:1): print splice@l,rand@l,1for@l=<>
DB<1> c
4
5
1
3
Attempt to free unreferenced scalar at -e line 1, <> line 5.
Bus error (core dumped)
Another time (while stepping through with 'n'), I got this error:
Attempt to free unreferenced scalar at /usr/local/perl/lib/5.6/perl5db
+.pl line 1447, <IN> line 7.
Yet another time, I stepped through with 'n' and it worked fine.
Potentially a bug in perl? | [reply]
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Re: (GOLF) Randomizing lines
by dragonchild (Archbishop) on Jul 26, 2001 at 17:50 UTC
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123456789_123456789_123456789_123456789_1234567
perl -e'@l=<>;print splice(@l,rand@l,1)while@l'
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Re: (GOLF) Randomizing lines
by Cirollo (Friar) on Jul 26, 2001 at 17:56 UTC
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(MeowChow) Re: (GOLF) Randomizing lines
by MeowChow (Vicar) on Jul 26, 2001 at 23:55 UTC
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39 chars:
| | | perl -ne'splice@l,rand$.,0,$_}{print@l'
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And here's a nicely obfuscated one at 49:
| | | perl -ne'@=[~~@=,$=]=($=[$==rand$.],$_)}{print@='
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MeowChow
s aamecha.s a..a\u$&owag.print | [reply]
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Re: (GOLF) Randomizing lines
by bwana147 (Pilgrim) on Jul 26, 2001 at 19:35 UTC
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Hey, here's another shot at 37 characters:
perl -e'print sort{int rand 2or-1}<>'
Update: oops! I hadn't seen tadman's Update 2.0... I'm too late :-(
--bwana147 | [reply]
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