PHP Puzzlet.

[swestrup]

I'm kinda new to PHP, and I'm wondering what is the best way to perform this operation:

I have three variables, $a, $b and $c. Each contains either a single character, or nothing.

What's the best way to test that no two defined values are the same?

Heck, I'm not even sure what the best way to do this would be in Perl, allthough I have a few ideas involving hashes.

Comments

[sps.livejournal.com]

Yeah, in Perl, you can do something perverted but cute like

sub coll(@) {my %a; @a{@_}=(); @_ == keys %a}

or more sensibly if less tersely

sub coll(@) {my %a; for my $a (@_) {return undef if $a{$a}++}; 1}

[sps.livejournal.com]

...Though for only three items, $a ne $b && $a ne $c && $b ne $c is likely fastest.

[swestrup]

Yeah, except that I think that undef == undef is true, and I only want existing elements to be unique.

[sps.livejournal.com]

Oh, sorry.

sub coll(@) {my @a = grep $_, @_; %a; @a{@a}=(); @a == keys %a}

or

sub coll(@) {my %a; for my $a (@_) {return undef if $a && $a{$a}++}; 1}

—but of course, that's still just Perl.