A little golfing challenge: replace digits by random letters

haukex has asked for the wisdom of the Perl Monks concerning the following question:

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Re: A little golfing challenge: replace digits by random letters by BrowserUk (Patriarch) on Feb 10, 2019 at 11:24 UTC
Not a perfect shuffle, but close (enough?) and much shorter: `perl -M5';$x=join"",sort{rand()<rand}a..z' -pe 'eval"tr/0-9/$x/"' input.txt` [download] With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity. In the absence of evidence, opinion is indistinguishable from prejudice. Suck that fhit	[reply] [d/l]
Re^2: A little golfing challenge: replace digits by random letters by bliako (Abbot) on Feb 10, 2019 at 13:02 UTC
half-blind-sort is a great idea (and so is `{rand()<rand}` ). Couldn't resist `sort{rand(2)-1}` as it's shorter by 2 and truer blind. Update/Correction: as vr rightly notes, `int(rand(2)-1)` is constantly 0!!! Because sort expects an integer back from the comparison BLOCK and `int()`'ing `rand(2)-1` leaves just 0 :(. So, both these compensate for that bug and are uniformly random too: `sort{rand(6)-4}` and `sort{1-rand(3)%3}`	[reply] [d/l] [select]
Re^3: A little golfing challenge: replace digits by random letters by vr (Curate) on Feb 10, 2019 at 14:12 UTC
Perhaps `sort{rand(2)-1}` (in effect, same as `sort{0}`) is somewhat too deterministic :). But `$ perl -E 'say sort{rand 2}a..z'` produces random enough strings, and is shorter.	[reply] [d/l] [select]
Re^4: A little golfing challenge: replace digits by random letters by bliako (Abbot) on Feb 10, 2019 at 15:28 UTC
Re: A little golfing challenge: replace digits by random letters (updated) -- oneliner by Discipulus (Canon) on Feb 10, 2019 at 13:49 UTC
Hello haukex, have you decided to consume all our spare times!?! ;) Not golfed but maybe of interest `perl '-M0;map{$h{$_}++}97..122;@a=map{chr$_}keys%h;$"=""' -pe 'eval"tr +/0-9/@a[0..9]/"' input.txt` [download] WebPerl link (requires haukex ;) L* UPDATE see it running `perl '-M0;$h{$_}++for 97..122;$"=""' -pe 's/(\d)/(map{chr$_}keys%h)[$1]/eg' input.txt` removing unneeded assignemnts.. `perl '-M0;$h{$_}++for 97..122' -pe 's/(\d)/(map{chr$_}keys%h)[$1]/eg' input.txt` or even.. `perl '-M0;@h{97..122}=1x125' -pe 's/(\d)/(map{chr$_}keys%h)[$1]/eg' input.txt` ... `perl '-M0;@h{97..122}=1x125'-pe 's/\d/(map{chr$_}keys%h)[$&]/eg' input.txt` ... `perl '-M0;@h{97..122}=1x125'-pe 's/\d/chr((keys%h)[$&])/eg' input.txt` ... `perl '-M0;undef@h{97..122}'-pe 's/\d/chr((keys%h)[$&])/eg' input.txt` ..stop! `perl '-M0;@h{97..122}=1'-pe 's/\d/chr((keys%h)[$&])/eg' input.txt` L* congrats Eily for the below reduction! another variation, not highly random.. `perl -pe 's/\d/(a..z)[$&-(split"",time)[-1]]/eg' input.txt` or.. (shorter than Eily's one ;) `perl -pe 's\|\d\|(a..z)[$&-time%7]\|eg' input.txt` after haukex's suggestion: `perl -pe 's\|\d\|(a..z)[$&-$^T%7]\|eg' input.txt` L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]
Re^2: A little golfing challenge: replace digits by random letters (updated) -- oneliner by Eily (Monsignor) on Feb 10, 2019 at 20:24 UTC
That's already impressive, but why bother with chr in the first place? `perl '-M0;@h{+a..z}=1'-pe 's/\d/(keys%h)[$&]/eg' input.txt` works just as fine. Edit: this can still be reduced a little: `perl '-M0;@h{a..z}=1'-pe 's/\d/(%h)[$&*2]/eg' input.txt` [download]	[reply] [d/l] [select]
Re^2: A little golfing challenge: replace digits by random letters (updated) -- oneliner by Eily (Monsignor) on Feb 11, 2019 at 14:23 UTC
or.. (shorter than Eily's one ;) `perl -pe 's\|\d\|(a..z)[$&-time%7]\|eg' input.txt` That's nearly always correct (if you ignore the fact that it's a shift, not a shuffle). You'll get different values if the lines are not treated in the same second. This would happen if the first line is handled at 9:59:59.9999 and the second at 10:00:00.0000 (add the proper number of digits). Or if you are working on a piped input from a slow program, or the input is big enough. This can be demonstrated by adding a sleep. I realized I could shorten the other version (I don't feel like calling it mine when I just took your idea and rewrote it :P), but it's still longer than your latest proposition: `perl -pe '@h{a..z}=1;s/\d/(%h)[$&*2]/eg' input.txt` [download] Because since this is golfing, why would you bother doing things properly/efficiently? :P	[reply] [d/l] [select]
Re^3: A little golfing challenge: replace digits by random letters (updated) -- oneliner by haukex (Archbishop) on Feb 11, 2019 at 14:26 UTC
You'll get different values if the lines are not treated in the same second. I had already `/msg`'d Discipulus about this - the time can be replaced by $^T `:-)`	[reply] [d/l] [select]
Re: A little golfing challenge: replace digits by random letters by bliako (Abbot) on Feb 10, 2019 at 17:16 UTC
rand knows all! `echo 123412341234 \| perl -pe '$s=time;s/(.)/srand $s;rand for 1..$1;ch +r(ord("a")+rand 26)/ge'` [download] bw, bliako Edit: fixed the 'a' to "a" also a warning: this code should not be run more than once during one whole second, thanks Discipulus Edit: Of course that warning is because of `srand(time)`. Now this seeds and on something completely different: `echo '01234567890123456789' \| perl -pe '$s=time+join "",{}=~/(\d+)/g;s/(.)/srand $s;rand for 0..$1;chr(ord("a")+rand 26)/ge'`. (👁️)	[reply] [d/l] [select]
Re^2: A little golfing challenge: replace digits by random letters by Discipulus (Canon) on Feb 10, 2019 at 17:45 UTC
Hello bliako, apart the typo ( `'a'` insted of `"a"`) I see duplicates in you code output and more characters than expected See it here L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]
Re^3: A little golfing challenge: replace digits by random letters by bliako (Abbot) on Feb 10, 2019 at 19:44 UTC
Hello there Discipulus, grazie for the alerts and for fixing the quotes issue serving me my own medicine. The duplicates are because you ran it too fast! You need to run this code once a second or slower. The universe needs some time to settle ... i.e. the RNG seeds on time whose granularity is the second. However, here is a version which seeds on something different: `echo '01234567890123456789' \| perl -pe '$s=time+join "",{}=~/(\d+)/g;s +/(.)/srand $s;rand for 0..$1;chr(ord("a")+rand 26)/ge'` [download] More characters than expected I have not observed. This test may be useful for others too: echo '01234567890123456789' \| perl -MTest::More -pe ' my $inp = $_; my $L = length($inp); my $N = 100; # number of trials $nt=0; my %previous = (); for(1..$N){ my $tmp = $inp; my $s = join "$_", {} =~ /(\d+)/g; # because ... $tmp =~ s/(.)/srand $s;rand for 0..$1;chr(ord("a")+rand 26)/ge +; $previous{$tmp} = 1; ok(length($tmp)==$L, "length of conversion (".length($tmp).") +equals expected ($L)."); $nt++; } ok(scalar(keys %previous)==$N, ($N-scalar(keys %previous))." duplicate +s among $N trials"); $nt++; done_testing($nt); ' [download]	[reply] [d/l] [select]