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### Re: Storing variable coordinates in a matrix

by davidrw (Prior)
 on Mar 15, 2007 at 16:46 UTC ( #605020=note: print w/replies, xml ) Need Help??

in reply to Storing variable coordinates in a matrix

the my @A assignment uses the values of \$x and \$y at that time, and then you get an AoA of static numbers .. changing \$x and \$y after the fact will have no effect. I believe what you're looking for is a function, so you can pass in \$x and \$y and get back the array calculated for those two values.
```sub makeBoxArray {
my (\$x, \$y) =  @_;
return (
[ ([\$x, \$y  ]), ([\$x+1, \$y  ]), ([\$x+2, \$y  ]), ([\$x+3, \$y  ]) ],
[ ([\$x, \$y+1]), ([\$x+1, \$y+1]), ([\$x+2, \$y+1]), ([\$x+3, \$y+1]) ],
[ ([\$x, \$y+2]), ([\$x+1, \$y+2]), ([\$x+2, \$y+2]), ([\$x+3, \$y+2]) ],
[ ([\$x, \$y+3]), ([\$x+1, \$y+3]), ([\$x+2, \$y+3]), ([\$x+3, \$y+3]) ],
);
}

my @A = makeBoxArray( 5, 10 );
# use @A for something
@A = makeBoxArray( 7, 2 );
# use @A for something
To take it a step further, the array can be generated using map to eliminate the repetitive text, and also add optional params for the box size:
```sub makeBoxArray {
my \$left = shift;
my \$top = shift;
my \$width = shift || 4;
my \$height = shift || 4;
return map {
my \$y = \$_;
[ map { [\$left+\$_, \$top+\$y] } 0 .. \$width-1 ]
} 0 .. \$height-1 ;
}

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