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ChOas has asked for the wisdom of the Perl Monks concerning the following question:
Hey People,
As usual leons and I were coding a bit, and tried
to find a way to mix n number of m lenght arrays
together, preserving the original order of the
original arrays
I came up with this:
#!/usr/bin/perl -w
use strict;
sub Mix;
my @Row1=(1,3,5,7);
my @Row2=(2,4,6);
my @Row3=(9,9,9);
my @Row4=Mix(\@Row1,\@Row2,\@Row3);
print "@Row4\n";
sub Mix
{
my @Result;
while(1)
{
my $Old=@Result;
push @Result,grep $_,shift @{$_} for @_;
last if @Result==$Old;
};
@Result;
};
Output: 1 2 9 3 4 9 5 6 9 7
Anyway to do it quicker/more efficient/shorter ?
GreetZ!,
print "profeth still\n" if /bird|devil/;|
Re: Mixing up da Arrays (Golf)
by jmcnamara (Monsignor) on Apr 18, 2001 at 18:38 UTC
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This is short but inefficient.
#!/usr/bin/perl6
sleep(31536000);
@Row4 = merge(@Row1, @Row2, @Row3);
The sleep() is there because we may have to wait a while for merge().
John.
--
There are PI seconds in a nano-century.
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(tye)Re: Mixing up da Arrays (Golf)
by tye (Sage) on Apr 18, 2001 at 18:02 UTC
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use mapcar;
my @mix= mapcar {@_}, \@a1, \@a2, \@a3;
-
tye
(but my friends call me "Tye") | [reply]
[d/l] |
Re (tilly) 1: Mixing up da Arrays (Golf)
by tilly (Archbishop) on Apr 18, 2001 at 19:39 UTC
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Do I hear golf?
First at 48 chars, the one that modifies the original
arguments like yours does:
sub Mix {
my@a;@_=grep{@$_?push@a,shift@$_:0}@_ while@_;@a
}
and a safe one that doesn't do that at 59 chars:
sub MixS {
my@a;for(my$i;@_;++$i){@_=grep{$i<@$_&&push@a,$$_[$i]}@_}@a
}
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[d/l]
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Re: Mixing up da Arrays (Golf)
by arhuman (Vicar) on Apr 18, 2001 at 18:44 UTC
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I'll definitly win the 'ugly one' contest with this one...
Its only advantage : it leaves the arrays passed as arguments untouched, (I feel that someone could make it smaller too)
The most bothering thing for me (apart from the nasty $i handling)is the stop test :
last unless (join'',@n)
Too long, and to weird, anyone to help me improve this ?
sub Mix2 {
my (@r,@n);
my $i=-1;
while($i++>-2){
@n=map{$_->[$i]}@_;
@r=(@r,@n);
last unless (join'',@n)
}
@r;
}
UPDATE :
To save one char and make it even uglier,
You can whange while($i++>-2) to while($i+++2)
(and my $i=-1; to my $i--; for another one)
"Only Bad Coders Badly Code In Perl" (OBC2IP)
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Re: Mixing up da Arrays (Golf)
by kschwab (Vicar) on Apr 18, 2001 at 18:24 UTC
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I have no idea if this is quicker or more efficient,
but it's uglier:)
#!/usr/bin/perl -w
use strict;
sub Mix;
my @Row1=(1,3,5,7);
my @Row2=(2,4,6);
my @Row3=(9,9,9);
my @Row4=Mix(\@Row1,\@Row2,\@Row3);
print "@Row4\n";
sub Mix {
my @Result;
for (0..scalar @{(sort {$#{$b} <=> $#{$a}} @_)[0]}) {
foreach my $a (@_) {
push(@Result,@$a[$_]) if ($_ <= $#{$a});
}
}
@Result;
}
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Re: Mixing up da Arrays (Golf)
by little (Curate) on Apr 18, 2001 at 18:04 UTC
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matrices
look up Math::Matrix for quick and somewhat magic number manipulation :-)
Have a nice day
All decision is left to your taste | [reply] |
Re: Mixing up da Arrays (Golf) (Russ=53)
by Russ (Deacon) on Apr 19, 2001 at 00:22 UTC
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I can get 53 for the safe version (see the post by tilly for details), though with (at least) one terrible inefficiency:
sub Mix{
map{my$i=$_;map{$$_[$i]}grep{@$_>$i}@_}0..map{@$_}@_
}
Russ
Brainbench 'Most Valuable Professional' for Perl | [reply]
[d/l] |
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sub Mix {
map{my$i=$_;map$i<@$_?$$_[$i]:(),@_}0..map@$_,@_
}
That matches what was done unsafely before. But
unfortunately for sanity's sake observe the following
33 character entry:
sub Mix {
map{splice@$_,0,1}map@_,map@$_,@_
}
I have written saner code...
UPDATE
Saved 3 chars on the unsafe example, there is no need
for a nice numerical list when I will be just converting
the elements...
UPDATE 2
Sheesh. And the safe example can be modified to the
rather bizarre 45 character beast:
sub Mix {
map{splice@$_,0,1}map@_,map@$_,@_=map[@$_],@_
}
UPDATE 3
I give up on shrinking this. However I have 4 variations
on the key 33 char sub. In terms of efficiency of
execution, the following wins:
sub Mix {
map{map{splice@$_,0,1}(@_)x@$_}@_
}
So that is (barring the unexpected) my final answer. | [reply]
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Re: Mixing up da Arrays (Golf)
by premchai21 (Curate) on Apr 18, 2001 at 22:25 UTC
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Not shorter, but more obfuscated:
sub Mix{map{my$a=$_;map{$$_[$a]}@_}0..Max(map{scalar @$_}@_)}
sub Max{my$a=shift;while(@_){my$b=shift;$a=$b if($b>$a)}$a}
print Mix([1,2,3,4],[5,6,7],[8,9,0]);
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