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in reply to Comparison by position and value

sub compatible { 
    my ($s1, $s2) = @_; 
    y/_/\0/c for $s1, $s2; 
    !(($s1 | $s2)=~y/\0//); 
} 
print(compatible("_8__3__19", "48_____7_") ? "true\n" : "false\n");

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Update: BrowserUK has pointed out that this is wrong. Indeed, it does not work if there is the same digit in both positions of the same string.

Update: Corrected (I hope) code 

sub compatible {
    y/_/\477/c, y/_/\0/ for my @m = @_;
    !((($_[0] ^ $_[1]) & $m[0] & $m[1]) =~ y/\0//c);
}

printf "%s v %s ? %s\n", @$_, compatible( @$_ ) ? 1 : 0
        for [ qw[ _8__3__19 48____7__ ] ],  # compat
                [ qw[ _8__3__19 4_8___7__ ] ],  # compat
                [ qw[ _8__3__19 48_____7_ ] ];  # clash

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Update: Oh, I've got it wrong again. forget this.

Replies are listed 'Best First'.
Re^2: Comparison by position and value
by BrowserUk (Patriarch) on Jan 02, 2005 at 11:21 UTC

    That doesn't work as is? 

    #! perl -slw
use strict;

sub compatible {
    my ($s1, $s2) = @_;
    y/_/\0/c for $s1, $s2;
    !(($s1 | $s2)=~y/\0//);
}

printf "%s v %s ? %s\n", @$_, compatible( @$_ ) ? 1 : 0 
    for [ qw[ _8__3__19 48____7__ ] ],  # good
        [ qw[ _8__3__19 4_8___7__ ] ],  # bad
        [ qw[ _8__3__19 48_____7_ ] ];  # bad
        
__END__
[11:18:29.65] P:\test>test
_8__3__19 v 48____7__ ? 0
_8__3__19 v 4_8___7__ ? 1
_8__3__19 v 48_____7_ ? 0

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    Examine what is said, not who speaks.
    Silence betokens consent.
    Love the truth but pardon error.
[reply]
[d/l]

      I don't see your problem: 

      _8__3__19 v
48____7__ ? 0
 ^

_8__3__19 v
4_8___7__ ? 1

_8__3__19 v
48_____7_ ? 0
 ^     ^

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      For these strings at least, the result is 0 iff there is a clash of two digits somewhere.

[reply]
[d/l]

        The first two strings are compatible, because they only overlap (contain a digit in the same place) where the digit is the same in both strings. Please see the 3 examples in the OP.

        Examine what is said, not who speaks.
        Silence betokens consent.
        Love the truth but pardon error.
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