<?php??
/**?
?* @param array $weight 權重? 例如array('a'=>10,'b'=>20,'c'=>50)?
?* @return string key?? 鍵名??
?*/?
function roll($weight = array()) {??
?$roll = rand ( 1, array_sum ( $weight ) );??
?$_tmpW = 0;??
?$rollnum = 0;??
? foreach ( $weight as $k => $v ) {??
? $min = $_tmpW;??
?? $_tmpW += $v;??
?? $max = $_tmpW;??
?? if ($roll > $min && $roll <= $max) {??
??? $rollnum = $k;??
??? break;??
?? }??
?}??
? return $rollnum;??
}??
?
$row=roll(array('a'=>10,'b'=>20,'c'=>50));??
echo $row;??
?>