use strict;

my @a = qw(a a a a a a a);
my @b = qw(a a a a a a Q);
my @c = qw(a a a M a a a);
my @d = qw(Z a a c a a a);

sub all_eq {
    my $first = shift;

    for (@_) {
        next if ($first eq $_);
        return 0;
    }
    return 1;
}

map { printf "testing @$_: -> %d\n", all_eq(@$_)  } (\@a, \@b, \@c, \@
+d);

[download]

Replies are listed 'Best First'.
Re (tilly) 1: Golf Challenge: all elements of an array equal
by tilly (Archbishop) on Jul 14, 2001 at 01:26 UTC
    17 chars. 
    sub all_eq {
!grep$_[0]ne$_,@_
}

    [download]
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Re: (Golf) All Elements of an Array Equal
by tadman (Prior) on Jul 14, 2001 at 07:36 UTC
    Like MeowChow's, 17 characters, but this one can be run more than once without error: 
    sub all_ne {
map{$_ ne$_[0]}@_
}

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    Update:
    Upon reading the entire thread, this does seem similar to what tilly posted. Strange. This means that I can now say: 
    sub all_ne {
map$_[0]ne$_,@_
}

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    Which is incredibly only 15 characters. Thanks to tilly for the obvious parameter re-ordering trick. I had been mashing around with grep during testing, but discarded it as too bulky.

    Update-2:
    For whatever reason, it seems I've implemented the function in the negative sense.
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[select]
      You should have stayed with grep. Try the following: 
      sub f{
map$_[0]ne$_,@_
}

print "Gotcha!\n" if f(1,2);

      [download]
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Re: Golf Challenge: all elements of an array equal
by jmcnamara (Monsignor) on Jul 14, 2001 at 02:45 UTC 

    sub all_eq0 {
    @_{@_}=2;
    !((@_=%_)-2)
}
# 21 chars but wrong as per MeowChow


sub all_eq1 {
    local%_;
    @_{@_}=2;
    !((@_=%_)-2)
}
# 29 chars


sub all_eq2 {
    my%h;
    @h{@_}=2;
    !((@_=%h)-2)
}
# 26 chars

    [download]
    Update: Spotted the mistake in all_eq0() but MeowChow beat me to it. And then beat me some more. ;-)

    John.
    --

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[d/l]
      Interesting method. The bad news is that it can only be used once (try princepawn's test case, setting @d = qw/a a a a a a a/). But the good news is that it can be reduced to 18 :) 
      sub all_eq {
  (@_{@_}=1)==keys%_
}

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      update: 17 chars... 
        @_{@_}=0;keys%_<2

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         MeowChow                                   
               s aamecha.s a..a\u$&owag.print
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Re: Golf Challenge: all elements of an array equal
by jmcnamara (Monsignor) on Jul 14, 2001 at 12:21 UTC

    A variation on the theme of map and grep in an avoid context: 
    sub all_eq3 {
    @_=sort@_;
    $_[0]eq pop
}
# 21 chars

    [download]


    John.
    --

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[d/l]

      My first instinct was to go the sort route, actually. You could shrink your solution by one:

      sub all_eq {
  #123456789_123456789_
   (@_=sort@_)[0]eq pop
}

      [download]

      His Royal Cheeziness

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Re: Golf Challenge: all elements of an array equal
by jmcnamara (Monsignor) on Jul 14, 2001 at 23:47 UTC

    I thought of this in the car this morning: 
    sub all_eq5 {
    "@_ "eq"$_[0] "x@_ 
}
# 18 chars

    [download]
    Update: Unfortunately, this methodology is flawed. It returns the wrong value for a list such as ('aa', 'aaa', 'a').

    John.
    --

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Re: Golf Challenge: all elements of an array equal
by jmcnamara (Monsignor) on Jul 14, 2001 at 12:23 UTC

    And another ... 
    sub all_eq4 {
    local$"='';
    "@_"eq$_[0]x@_
}
# 25 chars

    [download]
    Update: Unfortunately, this methodology is flawed. It returns the wrong value for a list such as ('a a', 'a a a', 'a').

    John.
    --

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Re: Golf Challenge: all elements of an array equal
by nakor (Novice) on Aug 14, 2001 at 18:47 UTC
    in perl6 (if Damian's goal of including Quantum::Superpositions comes true): all@a==all@b 12 chars! Woohoo!
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