note 111235 added to book.math

Provides a function to rescale numbers so that the range [a,b] fits into the range [c,d]. <?php function rescale($ab, $cd) { list($a, $b) = $ab; list($c, $d) = $cd; if($a == $b) { trigger_error("Invalid scale", E_USER_WARNING); return false; } $o = ($b * $c - $a * $d) / ($b - $a); $s = ($d - $c) / ($b - $a); return function($x)use($o, $s) { return $s * $x + $o; }; } $fahr2celsius = rescale([32, 212], [0, 100]); echo $fahr2celsius(98.6); // 37°C ?> ---- Server IP: 69.147.83.199 Probable Submitter: 122.57.198.66 ---- Manual Page -- http://php.net/manual/en/book.math.php Edit -- https://master.php.net/note/edit/111235 Del: integrated -- https://master.php.net/note/delete/111235/integrated Del: useless -- https://master.php.net/note/delete/111235/useless Del: bad code -- https://master.php.net/note/delete/111235/bad+code Del: spam -- https://master.php.net/note/delete/111235/spam Del: non-english -- https://master.php.net/note/delete/111235/non-english Del: in docs -- https://master.php.net/note/delete/111235/in+docs Del: other reasons-- https://master.php.net/note/delete/111235 Reject -- https://master.php.net/note/reject/111235 Search -- https://master.php.net/manage/user-notes.php